United States Customs and Border Protection agents have long had the authority to demand travellers provide access to their electronic devices, but what they’re looking for seems to have changed under the Donald Trump administration.

A French scientist on his way to a conference in Houston was recently turned away over alleged “hateful” messages found on his cellphone.

“U.S. Customs Border Protection, CBP, has the authority to search the devices of anybody travelling across the border, including U.S. citizens – and definitely Canadians,” said Cindy Switzer, a Vancouver-based immigration lawyer practising on both sides of the border.

In an interview with CTV News, Switzer said, in her experience, border guards generally used that power in the past to look for evidence of crimes such as drug trafficking and possession of child pornography.

But some recent examples show guards may be denying entry to foreign nationals based on political leanings discovered in their social media and messaging apps that do not align with the Trump administration and its policies.

“This measure was taken by the U.S. authorities because the researcher’s phone contained exchanges with colleagues and friends in which he expressed his political opinion on the policies of the Trump administration on research,” French Higher Education Minister Philippe Baptiste told AFP shortly after the incident involving the French scientist.

According to Switzer, CBP agents have wide latitude when deciding whether to allow someone into the United States.

“The issue is that border officers have full discretion in order to grant somebody admission, and they can deny somebody admission for any reason,” she said.

Mike Agerbo, a digital living expert and host of the Get Connected podcast, told CTV News people concerned about protecting their privacy while crossing the border should consider using a different phone than they normally carry.

Agerbo said that’s a good option for people who have an old cellphone lying around – provided they remember to factory reset it before using it and don’t load social media, mail and messaging apps onto it.

For those without a second phone to fall back on, he suggests doing a thorough examination of their devices and deleting anything that isn’t absolutely necessary.

“Just make sure that whatever you have on your device – whether it’s a laptop or a phone – is just basically bare bones,” Agerbo said. “And, if you are deleting things, make sure that they’re securely deleted and go into the deleted folder or the trash and make sure they’re deleted there as well.”

Lastly, Agerbo recommends travellers check privacy settings on social media accounts to make sure they are comfortable with any publicly visible posts which border guards might be able to find through a simple Google search.