Unless you're a crypomillionare with little other income (most of whom are probably smart enough not to risk it) the paying up part shouldn't be too hard.

I can't stress how common this is with cash only side gigs. People hope they don't get caught and if they get caught they play dumb and agree to pay X per month to settle the bill.

They need to show intent or get you to lie to them if they want to put you in prison (which they don't because they want your money instead).