<p>I’m not a lawyer, but the case law I’ve seen has been along the lines of the minor suing the custodian for breach of fiduciary responsibility, with the custodian often having to pay back the money and/or pay fines/court costs. I’ve never read of anyone being thrown in jail, and since UTMAs fall under state laws rather than Federal ones, I don’t think the IRS is going to come after you either. There’s no 10% penalty on withdrawals from UTMAs.</p>