What would you do if you heard the valet driving your car "spiritedly"?

Last night, in NOLA I ended up taking two of my younger cousins to a Pelicans game and out in the quarter for their birthday. Anyway, so we couldn't find parking, and I had to use the valet service in a parking garage. No biggie, I come back to pick up my vehicle, and I hear my car start up. Now, my exhaust is very loud with a very distinctive tone and very distinctive lope at idle. So I hear my car start. Then I hear an engine rev. At this point I'm all like wtf bro looking at the cashier for the valet service and she is looking back at me with a suprised look as well. I then hear my car go into reverse, once again, a very distinct lope in the exhaust sound/note) then again into gear, and off he goes, setting off another vehicles alarm I might add. He had to have been revving the car above 3500 Rpms xause that's the rpm range were my exhaust starts to get more raspy. Seems like he was flooring it on the straight aways down all 3 levels of the garage to the bottom floor. He gets out and I confront him like "wtf bro, why are you driving my car like that?" Even his manager questions him about it. He claims he wasn't driving it hard and never got above 10 mph. I know it's bullshite. His manager knows its bullshite. But there was nothing I could do to prove it besides maybe having a dash cam? What would the OT have done in this situation?