Simply put, if Canada hadn't denied her entry, the US would have been none the wise to her illegal/unauthorised work on her Esta and this whole situation would have been avoided.
Denial of entry over intended work essentially flagged the issue to the US of potential Esta violation.
Now the detention bit occurred due to it being a land border. The situation would have been different if going via the airport.
On trying to re-enter the US at a land border, she was deemed in-admissable under section 8 of the INA. In-admissible means that she could not be admitted to the the US and therefore detained.
The Guardian has so much misinformation and omitting of key facts because they are trying to push an agenda.
The French Scientist was in unlawful possession of classified material and even admitted on attempting to conceal it. Attempting to conceal classified material (stuff like this have special carriage instructions, needs signed papers and typically will require 2 people present for material security) is a sure fire way to have your phone checked.
Take the time to research the "victims" paraded in the media. I am yet to find one who was innocent where as tourists they had either violated/misrepresented the terms of their Esta/Tourist visa. Or as LPRs had violated Section 8 of the INA, something all LPRs must abide by (Something last amended in 2008 under Obama 1) for criminal charges/activity, drugs charges, leaving the country to skip court, terrorism/links to terrorism or by failing to meet the residency requirements set out for LPRs. As an Lawful Permanent Resident, you are required to be able to show residence and ties to the US. Any trips over 180 days will bring you scrutiny (this isn't new) and any extended trips for the 1-2 year mark, an I-131 re-entry permit needs to be applied for prior to leaving the US.
If I'd have done something that stupid. I'd be sat in Colly with my job gone, clearances gone and NSV pretty much hanging me out to dry whilst likely facing civilian prosecution after finishing time in Colly.
On the subject of phones. Again only those showing red flags will have likely their phones checked, as they will be the ones in secondary. They aren't checking phones randomly in lines.
Stats wise, for FY 2024 only 0.01% of travellers had their phones checked.
From CBP, roughly 1 million international arrivals occur every day across the US (tourists and returning visa holders). That equates to roughly 100 people across the entire US being in a position where their phones are checked. Spread between the all the airports, that is a very very small amount of people.
The misinformation, omission and covid level fear mongering from the media is abhorrent.
Honestly it angers me. Going through the already, long, stressful and torture like immigration process is hard enough already. But seeing this misinformation adding unnecessary and extra stress to those already feeling it is ridiculous.