But how are you "bringing your email into the country" any more than you would be if you just sent an email? If they can't access my sent email when I send it

But how are you "bringing your email into the country" any more than you would be if you just sent an email? If they can't access my sent email when I send it from abroad without a warrant, then how does me entering the country without a phone or computer allow them access to my email?