Originally Posted by dash1729

What you say--that you are legally in the US once you enter the preclearance area at a Canadian airport--seems to be true in some contexts but not in others. If one's flight is cancelled, for example, and one is forced to leave the preclearance area as a result, I believe one has to go back through Canadian customs as one has already legally left Canada.

However when purchasing food in the preclearance area, one still pays Canadian federal and provincial harmonized sales tax (HST). And I believe that if one were to commit a crime in the preclearance area, it would be prosecuted under Canadian, not US, law (after all, most crimes in the US are prosecuted under state jurisdiction and it isn't obvious which US state would have jurisdiction in a US preclearance area).