No valet key has appeared anywhere I have read.
A valet key should;
Open drivers door.
Start the engine and allow the car to be driven wildly up a winding driveway to the top floor of a parking garage with the sound of screeching tires echoing back down to you. This of course ruins the grand meal you have waited months for and will be paying big bucks for. Knowing full well that the same thing will happen when they bring the car back down and deliver it back to you in a cloud of smoke. You will of course ignore the hand held out for a tip. If you are lucky there will be no dents and no significant miles added to the odometer. As you drive away you will see in the rear view mirror the car jockeys waving and smilingly at you and giving each other high fives. You may or may not see the time to get to the top floor chalked up just like on Top Gear. That’s when you decide that next time you’ll take the clapped out wreck your kid drives.