Originally Posted by
rufflesinc
as a US citizen , I have been pulled for secondary twice, once at YYZ pre-clearance, and once at Detroit tunnel. So I think the more interesting question is what other information the officer sees that would get people into secondary
Given that I used US passport to enter the US, there shouldn't be any issue confirming that my passport is legit
Just because you're a US citizen doesn't mean you won't get directed to secondary. It just means they (USCBP) aren't allowed to refuse you entry. They can pull you or detain you as they are wont.
Depending on when and how far apart you were sent to secondary it could be any number of things... eg, you went to YYZ via air and returned via car (in a short period of time) which might have flagged you for something... or your name might have been similar to someone else that was on their watch list at that time. You could have been unlucky enough to been selected randomly twice (I know someone who was randomly selected for additional TSA checks twice in two years and those were the only flights they took during that time).
If it was more of a frequent occurrence (eg, several times in a short period) then maybe I'd be concerned. But twice, likely not.