I appreciate the concern but I don't do it. What are the statutes against this? Is it a felony or misdemeanor?

I don't think it'd be strictly illegal, they'd just have grounds to fire you if you ever refused a ride (that goes for both Uber/Lyft).

Maybe fraud and breach of contract if, in the full-time contract, it says "you affirm you do not have another full-time job that will interfere with this job".