"Okay, first of all, the burden to prove they've been here is on them. So if they can't prove it, they can't stay, and it's not our fault."
So if they can't prove it, then we're going to have law enforcement handcuff them immediately and escort them out to a waiting bus for deportation? Yeah right, and I've got a bridge in Booklyn for sale. The reality is that if they can't prove it, an overwhelmed, disinterested, and incompetent bureacracy is going to wave them through anyway.