Facts-the sign's right
1) If you are in the shop and something bad happens, the dealership or shop is UNINSURED. That means if you sue them, they are on the hook for whatever the damages are. I have seen an entire dealership go under because one of the techs let a customer come see their car, then an overinflated tire blew... guy lost some hearing, sued the store, insurance co. said no dice because you let uninsured non-employees in in contravention of insurance policy rules. Store died because dealer couldn't pay, 20+ ppl out of work. All because the tech was a "nice guy". Next time you feel the urge to spectate, find the DEALER PRINCIPAL or the owner (not an employee) of the shop and ask if he minds you circumventing all those insurance signs. It's their a$$ on the line, not the techs or anyone else's. My guess is they say no.
2) Paying a labour rate doesn't give you the right to watch and interact with the tech. Quotes are based on how much time the repair takes to complete, and are calculated without someone watching and asking questions, which slows down the job. Alot.
3) Do you go into the kitchen and watch the cooks prepare your food when you order a meal at a restaurant? When you purchase an airline ticket, do you get to sit behind the pilot and give him flying tips? In your own line of work, are customers welcome to hang out at your desk , watch you all day and give you helpful pointers? Nooooooooooo. So why is this different?
4) If you distrust the shop enough to have to watch them work on your beater, find another shop. It's not a healthy relationship.
5) Some techs don't like people looking over their shoulder. If you are really chatty , critical of their work, and helpful while you watch them work on your car, they might even torque your wheel nuts to Schwarzenegger-tight and slack off your valve cores just a bit before putting your valve stem caps back on, so when you wake up in the morning you're on 4 flats and no hope of undoing even 1 lug nut. Seen this happen once.
Car.B.Que