The FMCSA/Dot/State patrol etc. have nailed guys for hauling race vehicles across state lines if it is proven that they have sponsorship or there's a purse. This is a ridiculous process to go through just for someone having a bit of fun, little more than a hobby. Most guys nailed for this aren't professional race teams.
But there's good news! The DOT is going under a regulatory review. With your input maybe we can get this changed for anyone less than a professional level. Here's the link:
Regulations.gov