While there's U.S. Customs agents in Pearson, the entirety of security is done by CATSA. I cannot imagine U.S. Customs doing any sort of pat down. I'm not sure

While there's U.S. Customs agents in Pearson, the entirety of security is done by CATSA. I cannot imagine U.S. Customs doing any sort of pat down. I'm not sure they'd even be allowed to do anything like that in Toronto. I think they're pretty much only allowed to screen and admit or reject.