Apparently not very well, as they have even gathered up US citizens, and people of near their targets, not even involved with their target. Don't put much faith in their supposed "verification", as they are looking for numbers to deport, sometimes not even checking ID before hauling them off. It is not a good time to be on the street looking Hispanic, even if born here from parents born here. They pick them up. Somebody else will have to sort them out, but without hearings or representation, that is pretty iffy and mistake have been and are being made.