With cannabis legalization on the horizon in Canada, US border guards are saying they will be looking for "red flags" when people try to cross. And a Buffalo-based immigration lawyer says your choice of t-shirts may be all it takes to get turned back.

While Canada moves ahead with marijuana legalization, Congress steadfastly upholds prohibition. That ban not only forbids American citizens from using marijuana for medicinal or recreational purposes, but it also allows border guards to turn away visitors if they so much as admit to having smoked marijuana in the past. And getting turned away once for cannabis can be enough to get slapped with a lifetime ban from entering America. 

"[That] has always been a potential hazard for Canadians," Matthew Kolken, a Buffalo immigration attorney told The Buffalo News. "And as a result of the legalization of marijuana in Ontario, it's likely it will be seized upon even more."

And guards are already gearing up for legalization, according to Aaron Bowker, who works for US Customs and Border Protection in Buffalo. Bowker says that while officers have been trained in how to detect impaired driving, travellers shouldn't notice any changes. There won't be more officers or any changes to the standard list of questions, he says. But officers will be looking for individuals transporting large amounts of cannabis.

"Officers are looking for red flags, and sometimes it's not just one red flag; sometimes it's three or four red flags," Bowker told Buffalo News.

While Bowker assures that there will not be any profiling happening at the border, the 'red flags' he speaks of sound like profiling by another name. Things as simple as your taste in music could be enough to initiate a more in-depth search of your person and vehicle, according to Kolken.

"Try driving up to the booth in your 'Steal Your Face' Grateful Dead T-shirt and see if you're not diverted to a secondary inspection."