Legal experts share 8 things you should never do when passing through airport customs

There's a trade-off with international travel : You get to experience new places, escape your daily routine and maybe even visit friends and family abroad. But you also have to deal with some logistical stressors, like navigating border inspections and customs. While the vast majority of international travelers clear border inspection without issue, some are referred to secondary inspection and, in some cases, denied entry.

• Related: What customs agents actually look for when you reenter the U.S.

To find out how to increase your chances of an easy experience, we checked in with legal experts from around the U.S. Here, they share the top mistakes travelers make at ports of entry, like misunderstanding declaration rules and underestimating the seriousness of border checks.

One note on terminology: Technically, "customs" refers to the process through which goods, currency, gifts and other items are declared, regulated and, in some cases, inspected. Border inspections, meanwhile, focus on travelers and determine whether they're allowed to enter a country. This article discusses the combined process of customs and border inspections.

1. Acting too casual with the officer

"A customs officer isn't your buddy, and the booth isn't the place for jokes," says Joseph Kwon, a business immigration attorney and the founder of Joe Kwon Law . "Answer what's asked, keep it short and skip the comedy." While it might seem obvious, this is the number-one piece of advice we received from the legal experts we spoke with.

Jimmy Lai, an immigration attorney at Lai & Turner Law Firm PLLC , says that simply talking too much is the most common mistake he sees. "People get nervous in that line, and nervous people ramble," he says.

Instead of oversharing, Lai recommends just answering the questions you're asked, telling the truth and leaving it at that. "Don't joke, ever," he says. "Whatever joke you're about to make, the officer has heard it a thousand times."

2. Misrepresenting your reasons for traveling

At many ports of entry, you'll be asked a series of questions about your travel plans and potentially some additional questions about your job, income, immigration status and more. The most important thing to remember during this process? "Never misrepresent why you're traveling," says Lai.

Saying you're a tourist when you're actually planning on working (even if it's work-trade or pet sitting) isn't a white lie — "it's a false statement to a federal officer," says Lai. Kwon agrees: "If the honest answer feels complicated, sort it out before you fly, not at the desk."

Being completely honest in your answers also means your story will remain consistent, which border officers look for. "Customs officers are trained to detect inconsistency," says John Rose, chief risk adviser at Altour , a corporate travel management company.

"Even seemingly minor inaccuracies can raise concerns about credibility," adds Rehan Alimohammad, an immigration attorney, professor of practice at the University of Houston Law Center 's Immigration Clinic and a partner at Wong Fleming .

3. Talking on the phone anywhere in the inspection area

It should go without saying, but the inspection area is not the place to make phone calls or catch up on texts.

"Scrolling or taking a call while you wait reads as distracted at best and evasive at worst," says Kwon. "You want to look like someone who's paying attention." If an officer sees you as distracted or disrespectful from the get-go, this may not bode well for your interaction.

This advice was unanimous among the experts: "Don't talk on your phone … wear headphones or ignore instructions from customs officers," says Alimohammad. "Customs and border inspections are government screening processes, not customer service interactions."

4. Guessing or fudging the details on your customs form

Customs declarations may require travelers to report goods, currency, gifts, food, plants and other regulated items they are bringing across the border. Even if it seems a bit tedious to list out everything you're carrying, legal experts say you should not guess or estimate these things. If you're unsure whether something needs to be declared, ask.

And whether intentional or not, you shouldn't fudge any numbers or details at customs. For example, Lai says it's important not to "round down" the amount of cash you're carrying. You also shouldn't skip declaring things altogether because you assume it's unnecessary. "'I didn't think it counted' is probably the most expensive sentence in customs law," says Lai.

5. Thinking 'duty-free' means 'customs-free'

Thanks to the sprawling duty-free zones in airports, shopping at the terminal can feel like a free-for-all. But this doesn't mean you won't be on the hook for declaring your haul at customs. "Duty-free means you skipped the tax at the register, not that the stuff is invisible when you land," says Lai. "You still declare it."

The same is true for anything else you purchase in the airport or collect on your flight. Any food, beverages, gifts or other items you acquire before approaching the customs desk may need to be declared. Some food and drinks are a no-go at customs, so you may need to finish consuming these (or toss them) before getting in line. Keep in mind, though, that customs rules vary from place to place, so you should familiarize yourself with what is and isn't regulated where you're traveling.

6. Attempting to sneak prohibited items across the border

If " smuggling " sounds like a serious offense, that's because it is — and it's easier to be guilty of than you might think. If you knowingly refrain from declaring a controlled item to an officer because you want to sneak it through, this may be treated as smuggling or another customs violation, and it can land you in real trouble.

Remember that many items are prohibited or restricted from crossing international borders, even if they're perfectly legal where you bought them. Something as seemingly harmless as a packet of seeds can raise alarms due to strict regulations on agricultural products. The list of prohibited and restricted items in the U.S. is a good starting point, but don't forget to check the restrictions for any country you plan to visit.

7. Being careless about what and how you pack

Kirk Evans, attorney and president of U.S. LawShield , says quick, forgetful packing decisions can lead to problems at the border.

"A single forgotten round of ammunition, a small container of pepper spray, a pocket knife or another everyday self-defense item can be classified as a prohibited weapon," depending on where you're traveling, says Evans — even if you genuinely didn't mean to pack them. "Before leaving, completely empty and inspect every piece of luggage, including pockets, linings and hard-to-see crevices."

This also means never transporting packages or bags for someone else, "without knowing exactly what's inside," says Seann Malloy, founder and managing partner at Malloy Law Offices . "What feels like a harmless oversight at home can become a serious legal matter once you cross an international border," says Evans.

8. Being argumentative or confrontational at the border

Tensions can run high during border inspections, especially when long-awaited plans are on the line or you just want to go home. But letting those emotions spill over onto an officer is never a good idea. Put simply, "don't argue at the booth," says Lai. "You will never win an argument at a port of entry." If something really goes wrong, "fix it later with a lawyer if you need one."

Alimohammad shares similar advice: "If a traveler believes a question or decision is unfair, the airport inspection area is usually not the place to litigate the issue." Even when things are feeling stressful, "remaining calm and respectful is almost always the best approach," he says. "Most customs interactions are completed quickly when travelers approach the process with professionalism and common sense."

At the end of the day, "customs rewards boring," says Lai. "The people who breeze through are the ones with nothing interesting to say — be one of them."