How hard is it, in these days of computerized everything, to set up a system where the visa's expiration date and user's ID is logged. At expiration, if the visa doesn't show the user has left, issue a Federal arrest warrant. At some point it will catch up to them.
Advertise that fact.
Basically they have the system in place with a few tweaks of the data programming, imo.
The biggest problem would be to find out where these people are located now. I read
this as they have meld into the population and aren’t keeping the Visa group appraised.
So it becomes a search function to try and find them.