I think this is a really good question. Honestly I dont think it would hurt them to do either (lower rates or take up something part time). Only real problem I see is if they get a typical, run of the mill job it isnt going to pay them 200 (or more) an hour and instead take several eight hour days to make it. For some, a little perspective might actually do them good. Others, probably not so much.
Taxes? If they are smart, they will at least declare some of their income for tax purposes. It might look suspicious being able to afford the expense of daily living but not have any source of income paying for it.