Members need the ability to pay court fees of a nonmember at time of private booking

I realize there are "workarounds" - e.g. the member can add guest, or, this can be adjusted by the admin at the front desk, but, those workarounds don't really work well.  what's needed is, when a member books a court and adds a friend to the court who is in the system as a nonmember, that they can click to cover their court fees.

best example is parents paying for their kids court fees, when their kids are in the system but don't have a credit card on file.