CBP agents at the crossings in New York State already confiscate their fair share of marijuana on a daily basis.

Sometimes traffickers are trying to smuggle it across in large quantities, other times it's left in the pockets of those who use it personally.

Now that marijuana will be legal in Canada, American agents are expecting to find it more frequently.

Chief Customs and Border Protection Aaron Bowker tells News10NBC that there won't be stepped up enforcement, there will just be continued enforcement.

Everyone crossing into the United States will be asked where they were and what they were doing, and you may now be directly asked whether you used marijuana.

Aaron Bowker (CPB): "They could be asked. Do they ask every single time? No. It all depends on what the officer sees and what their perception is at the time but it is a question they could be asked, sure."

News10NBC Investigative Reporter Jennifer Lewke: "And if someone tells you, 'yes that's where I was'.. does that increase the level of scrutiny that they'll be under?

Bowker: "You could get a follow-up question, like, 'are you bringing anything with you?'"

Lewke: "And you expect most people to be truthful?"

Bowker: "Not telling the truth is just going to lead to more questioning and these officers are experts in lie detection. Not telling the truth is just going to make it harder for you to cross the border."

Lewke: "You're not supposed to bring it back with you. What happens if you have it or your found in possession of it?"

Bowker: "Well, right now it is still illegal in New York State so depending on the amount you have, you could be subject to arrest either locally or federally and you could also be subject to a fine, starting at $500 and up depending on how many times we find you in possession."

Lewke: "The bottom line for people?"

Bowker: "Make sure it's not on you, it's not in your car and you're not driving while impaired."

American citizens can't be denied entry back into the United States but local police will be called for anything more than 25 grams which is enough weed to fill up a standard zip-lock bag.

Anything less will be confiscated and you'll be fined $500-$5,000.

CBP also keeps permanent records so if you're busted for possession at the border, you'll be subject to more stringent inspections every time you try to cross in the future.

Canadian Citizens who admit to any usage at all, could end up being barred from entry into the United States.

"Marijuana is still a schedule one substance in the United States and so it is illegally federally in the U.S. and I think that can be confusing for a lot of travelers because under several different state laws cannabis is legal," says Danielle Rizzo, immigration attorney at Harris Beach.

Rizzo has a lot of Canadian clients who work in the U.S. and right now there's some uncertainty about whether they'll be admitted into the country if they even invest in the marijuana industry in Canada, let alone use the drug.

"We can't offer any blanket guidance on what's going to happen in any particular case…there are really gray areas and so our role as attorneys is really to advise them of the potential consequences of different courses of action," she tells News10NBC.