Most of us have been there.

Traveling either for work or pleasure we are returning home. We did a little shopping — okay a lot of shopping — and exceeded the maximum allowable purchase of duty-free items. Now we are standing in the customs line asking ourselves: Declare or not declare? According to experts like Avi Grossman who is in charge of customs inspections at Israel’s Ben-Gurion airport the answer is obvious: Declare declare declare!

Grossman and his colleagues have spent years observing how travelers act when returning to Israel which includes walking through the “Green Lane” as the locals refer to the customs lane for people who presumably have nothing to declare. And he knows what signals to look for.

“People who have something to hide do not walk slowly in the Green Lane” explains Grossman. “They move quickly in an effort to get past us as quickly as possible. Even if they wanted to act in a different way they would be unable to. To mask their tension they pretend not to notice the customs officials. They might speak on their cellular phones while passing through Green Lane. Or some of them wear sunglasses to hide the expressions of fear in their eyes.”

Sometimes though it isn’t a person’s physical behavior that will raise suspicions but their circumstances. Yoram Aharoni another customs official at Ben-Gurion relates how he caught two young Israeli girls attempting to smuggle cigarettes into Israel. “The girls left Israel for Moscow in the morning and returned that very evening. When two young girls travel alone to Moscow for such a short time we find that suspicious ” Aharoni explains. To make matters worse the girls weren’t exactly traveling light. “They arrived carrying large duffle bags which is not the kind of luggage that usually accompanies a young girl on her travels.”

Aharoni stopped one of the girls whose suitcase was filled with no less than one hundred cartons of cigarettes each one containing ten packs. The girl’s traveling companion initially slipped by Israeli authorities but was later located and brought to the airport with her parents who were forced to pay a hefty fine that amounted to hundreds of thousands of shekels since neither the tax on cigarettes in Israel nor the fine for smuggling them is cheap.

Perhaps though you’re thinking: Okay that’s Ben-Gurion. Everyone knows the Israelis are the best when it comes to security. But since when do I have to worry about those sleepy-looking officials at my hometown airport in New York or LA or Toronto? 

Since now according to the Transportation Security Administration (TSA). Working with psychologists and borrowing a page or two from the Israeli airport security model the TSA is developing new strategies for spotting terrorists smugglers and generally honest people who succumb to the temptation of lying when they’re in an airport rather than declare their purchases. Should the TSA’s efforts succeed passengers could see less invasive measures while checking in but closer scrutiny in the customs hall.