Yes, you are correct. Your W will PERHAPS face some sort of financial penalty but jail time is very unlikely. The true offender will be the entity that is paying their employees under the table and that is where punishment by law *may* come into play. And what her father does has little bearing on her parenting style. If you are putting *all* your hopes in that basket, again, get a better attny.
Years ago I worked at the Marriott hotel and they (they = Marriott) were not correctly entering our tips as wages. The Marriott Corp. was fined something huge and was responsible for ALL the employees financial penalties.
At best your W would have to pay back taxes and penalty on any unclaimed wages from a sole source that exceeds 600.00 per year. Unless you are talking millions of dollars then it seems silly to even talk about it.
And if your ex does "stuff" like you mentioned "all the time" why not purchase what your D DOES need then ask your ex for 50% reimbursement. That is the high road then you won't have to worry about your D having the wrong size stuff.