Don't forget that the paperwork costs a lot, if one has children, can get close to $10k.
Look at Spain -- instead of deporting "illegals", they just made them "legals" (those without a criminal record). Easy, problem solved.
Levity aside, working on a tourist visa is a violation but generally isn't prosecuted as a felony.
Also the grandparent post said "They seized a white Irishman last October who had a valid work permit and was just about to head to his green card interview."
If he had a valid work permit I suppose this means that he was allowed to work and pay taxes on that work, in other words - no, he was not committing a felony.