i used to be a valet...way back in highschool and i never abused cars. i drove tons and tons of nice cars. neither me nor my coworkers at the time abused any of them. unless you count stalling of course (tough driving all sorts of different clutches). ive driven everything from vanilla civics to maserati's and ferraris. the only car i DID abuse was a 996 turbo droptop with a tune. was valeting for a private party at a mansion at the time and our lot was probably an 1/8 mile up the mountain. needless to say, he threw me the keys and told me to let him know what i thought of his new tune. ill never forget the sheer amount of torque that car put out...its likely the fastest car ive ever driven.
with that said, i dont normally valet my z, but i did do it one time. asian kid that reminded me of myself got in and parked it within viewing distance. he also ran to get it when i returned and complimented the car. although ive never had a bad experience, theres definitely valets out there that will abuse your car. its hit and miss...but im hoping to get an uprev tune in the future for that sweet valet mode (the one that you can activate through the cruise controls)