Facing the threat of a lifetime ban from the U.S. for being involved with weed — even after it's legal — a number of Canadian cannabis executives have stopped travelling there altogether for business, while others have come up with tactics to avoid getting banned during trips south of the border.

While Canada is just weeks away from opening its recreational cannabis market, the substance remains illegal federally in the U.S. And industry insiders have speculated that the ban threat might be an attempt to curb the flow of capital from Canada into states that have legalized cannabis.

Concerns around what will happen to Canadians who use cannabis or work in the legal industry as they cross the border resurfaced on Thursday after a senior U.S. border official told Politico what Canadians could face at the border if they use cannabis or work in the industry. Border agents have sole discretion to allow or deny entry.

“Our officers are not going to be asking everyone whether they have used marijuana, but if other questions lead there — or if there is a smell coming from the car, they might ask,” Todd Owen, executive assistant commissioner for the Office of Field Operations, told the news outlet. “If you lie about it, that’s fraud and misrepresentation, which carries a lifetime ban.”

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Those who work or even invest in the industry that is legal in Canada, or other countries, but federally illegal in the U.S. could also be denied entry. “Facilitating the proliferation of the legal marijuana industry in U.S. states where it is deemed legal or Canada may affect an individual’s admissibility to the U.S.,” Owen continued.

A number of Canadians who have been barred from entry are those who have investments in the American cannabis sector, or those who have admitted to using cannabis when asked. Canadians who get banned may request a special, and costly, waiver to get enter the U.S. That process is complicated and waivers are granted at the discretion of border agents.

For one Canadian cannabis executive and investor, the comments by U.S. officials are an attempt to scare away Canadian investment in businesses in states that have legalized cannabis.

“This is a dog whistle meant to chill the flow of capital from Canada into the U.S.,” said the executive who requested anonymity due to the fact that he has exposure to U.S. cannabis ventures and travels there frequently for work. He said identifying himself through the media on this topic might increase the chances of him being denied entry.

“If you can’t stop it but you don’t want it to expediently develop, all you can do is slow it down. One way to slow it down is make the capital providers a little more concerned about the impact on their life,” he continued.

He also warned Canadians not to get too panicked after legalization.

“I don’t think we need to be too overwhelmingly paranoid about this because I know literally hundreds if not thousands of people who are in this industry who cross frequently and, with only one exception, no one has had a problem,” the executive explained.

Like other Canadian cannabis executives, he has adjusted the way he travels to the U.S. But, he says he will always tell the truth about his line of work when if asked about it.

“I’m not going to cross in the car anymore. Everybody I know that’s gotten dinged crossed in a car … I think it’s just safer to cross in an airport,” he said, pointing to the comments by the official in the Politico piece that described how the scent of cannabis or residue in one’s car could be grounds for further questioning by border agents.

Further, he said he will no longer travel to the U.S. from Billy Bishop airport in Toronto where there is no U.S. Customs pre-clearance, unlike at the city’s main Pearson airport.

If denied, “I’d prefer to go home then be like, for example, in a holding cell in the New York airport,” said the executive. “No thank you."

Chuck Rifici, an Ottawa-based cannabis CEO who founded cannabis giant Canopy Growth Corp., told VICE News that he no longer travels to the U.S. on business due to the uncertainty, or outright denial, he could face at the border because of his work.

“It’s a concern every time I cross the border if I’m going to get questioned on this industry,” Rifici told VICE News.

He said he made the decision not to travel for business a few months ago in the wake of the case of Vancouver cannabis businessman Sam Znaimer getting banned from the U.S. over his investments in American cannabis companies.

However, Rifici also had his own run-in with U.S. border agents in 2017 when his Nexus card — a pre-clearance permit granted to people eligible for expedited travel between Canada and the U.S. — was revoked after he was questioned by a U.S. border guard for two hours at the Ottawa airport.

Rifici said his card was stripped because he was attempting to carry a cannabis vape pen prototype over the border that was deemed in violation of Nexus provisions that forbid entering with a commercial product sample.

“The only reason that interview started was because I work in the canadian cannabis,” Rifici explained. “The border guard couldn’t understand how I got a Nexus card when I did something that was ‘illegal in America,’ as he put it.”

Since that experience, Rifici explained that he also clears his cell phone anytime he travels to the U.S. “Having your device searched and being interviewed ... it’s an experience that stays with you,” he said.

Canadian minister of border security and organized crime, Bill Blair, who also helped bring about the federal cannabis legalization legislation, told VICE News in a statement through a spokesperson that "Despite one-in-eight Canadians using cannabis today, 400,000 people move between our two countries every day almost entirely without incident."

"Officials from the United States have said that they do not plan on changing their questions at primary inspection after cannabis is legalized in Canada. However, if a traveller gives them reason to be suspicious, their officers may ask further questions," the statement continued.

"We want to identify and mitigate, as much as possible, any concerns regarding border enforcement. Our goals are to ensure that travellers are aware of regulations and what to expect when crossing border."