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.
Yes, that would be a problem. If they would be considered as an illegal immigrant from a tracking standpoint, they they would be in the system and eventually would be nailed. At least we could make 'em look over their shoulder.
Or, if at the time they were issued a visa, they were told they would be entered into the system after expiry date, with associated penalties, maybe that would encourage them to leave on time.