... one which Trump himself negotiated and signed during his first term.

I'm not trying to reassure anyone. I'm explaining that US pre clearance is not US soil, it's Canadian soil, and what they can do there is very limited relative to what they can do in the US at actual US ports of entry. The "preclearance is US soil thing" is a common misunderstanding.

It is not US soil, it is not an embassy. Actions there are governed by the Preclearance Act (which is reciprocal, btw, Canada has the right to open precleance facilities in the US - it just hasn't made sense due to the relative volume of flights).

They can only detain you until they hand you over to the Canadian police. [1]

Section (2) clearly states...

> (2) A preclearance officer is not permitted to exercise any powers of questioning or interrogation, examination, search, seizure, forfeiture, detention or arrest that are conferred under the laws of the United States.

[1] https://laws-lois.justice.gc.ca/eng/acts/P-19.32/FullText.ht...

Preclearance happens on Canadian soil, it's not an embassy. They would have to literally kidnap you and take you on a commercial flight to the US. If you're worried about the US kidnapping you from foreign countries, then I strongly suggest you speak to an attorney because I suspect you have bigger things to worry about than a Florida vacation.

[edit] Ah, I see, I didn't catch that you meant on arrival. I suppose that is a risk, but it does seem like you'd really have to make someone's shit list to be admitted only to then immediately be removed.