Thiago, like most valet workers, is prone to having a little fun with the cars he is entrusted to park... especially with the more expensive sporty cars. That's just genetics.
Young men and women are genetically wired to take chances and to pursue adventure and pleasure. Of course they are going to rev up the louder engines and go a little too fast in the garage. That's normal.
Thiago really likes this Maserati. You can tell. Those engines are loud too, I know. I drove plenty of them.
The thing with Maseratis and all the other fancy sporty cars is—it's no big deal to drive them after you've moved 30 or 40 or 50 of them. So it looks like Thiago is still fairly new to valet parking, though it appears they trust him enough to drive high value cars.
There are a bunch of things wrong here...
A valet should just park it and run back to his or her post. There should be no monkey business or fooling around with a customer's car.
A customer's car should be respected. No stomping on the gas. No needless revving of the engine.
Those are the minor issues here with Thiago.
A valet company should have a strict social media policy that specifically forbids their workers from producing any content for broadcast or publication while on the job. And maybe "Safety Park" has that policy.
Unfortunately for the valet company, whether this activity is forbidden in their employee handbook or not, this worker of their's has created a situation with his Youtube videos that could damage the reputation of their company and cost them business. (If they lose one account over it, that is very costly.)
The main issue, in my opinion, is the valet being distracted with his phone, or whatever the device is that is recording. Driving while distracted, in an unfamiliar car, in a car that doesn't belong to him... that invites misfortune.
An accident could happen. He could crash. He could injure a pedestrian.
Distracted driving is the worst thing he is doing. Setting-up his employer for bad PR and all the embarrassment, reputation damage, and stress that goes with that is the next worst thing he did.