BS. It's called Due Process. That's when you "can tell."
Due process would require that they actually catch the runners. ;-)
BTW there is really not much due process involved. Illegals are seldom
in any position to get a lawyer. They just get on the bus and go back
to Mexico.
You don't need a lawyer for Due Process to happen. Those who are found
to be illegal get an opportunity for a hearing and are processed in
the normal way.