Roadside valet parking operations are the highest risk.
When I was in Miami Beach a couple months ago, I saw a number of valet operations. One of them only had a rinky-dink little sign along a street. They didn't even have a valet podium (to store keys) or an umbrella. I figured if they weren't legit, the other valet stand half a block down the street probably would have ratted them out.
How difficult would it be to set-up a phony valet parking operation?
Probably not difficult at all.
A brand new valet podium, plus delivery, costs around $1000 to $1200. Having some shirts screen-printed with the words "VALET" on them: $100 to $250. Valet tickets: $100 to $150. Signage: $100 to $300.
So for an investment of less than $2000, somebody could create the appearance that a valet location along the street is legitimate—with uniforms, signage, claim tickets, and podium.
On a busy event night somewhere, they could probably easily get the keys to 10 to 30 nice cars handed to them within an hour.
The less desirable cars they simply park somewhere. The good ones get their GPS locators deactivated and put on a truck.
The last fake valet simply abandons the props and they are gone.
When the people come back, they stand around waiting for a valet to return to the valet podium. That buys the crooks more time. And by the time the police get involved, those missing vehicles are already loaded on to shipping containers, ready to begin their journey to a country in Africa.
I haven't heard of any car thieves being that sophisticated, but it's probably just a matter of time.
Roadside valet operations are higher risk.
They are too easy to set-up.
And if those valets are legit, they can be distracted while somebody gets into the key cabinet, or they might forget to lock that cabinet and then later discover that somebody grabbed some keys.
Valet operations that have a cashier's window with the keys being on a key board inside a locked cashier's office—that is manned at all times—are a safer type of valet operation. It is a lot harder to fake that, and the keys are more secure.
And even safer, I believe, would be an on-demand valet parking operation... because as a part of conducting the transaction, the on-demand valet must show you a "handover code" upon meeting you. If that code does not match the code the app is showing you on your phone, then it's pretty simple: you don't hand over your key.
On-demand valet parkers are not dealing with multiple cars at one time. They are not leaving cars running unattended with the keys inside of them, as a traditional valet parking operation might sometimes do. They only deal with one car at a time. It all adds up to being a safer valet parking choice from a car theft perspective.