Since it violates THEIR (both PayPal and Ebay) rules it doesn't matter what state you are in. (In some states you might also be breaking the law.) You have no legal entitlement to use either of these services. As such, you either follow their rules including no surcharges or YOU don't use their services. I think you have it backwards. If a seller tries to impose the surcharge report them to PayPal and Ebay (if applicable) and they will take appropriate action such as ending the auction or closing the offender's account.
GatorJ 1996 300ZX NA 1970 Fairlady Z 2002 Ford Escape XLT