@Ser****
so where's the evidence for this? 99%+ of the time, I honestly don't think they look into it. If you got it, you got it. What can happen, is that person will be unable to get their NEXT extension. That's what usually happens when there is a crackdown on something, existing people are unaffected, but they can't use the loophole any more.
Even past crackdowns they have had on people who were not really studying properly on Ed visas or not really volunteering properly on those visas, what happened was they grilled them on their next extension and denied them extensions. There have never been mass arrests and IDC and deportations over this stuff, that's a fantasy and doesn't happen.
Any stuff you find about mass roundups of foreigners, it's not Westerners that used dodgy agents.