SHAKES, I’m a little late, but I’ll add my 0.02 anyway. That was a really bad idea. I was once a cab driver in the DFW area and I’ve done that gig a few times. Your average teenager isn’t equipped to handle all of the things that could possibly go wrong.
He would be sitting alone in a car in a parking lot outside of a bar. He would be bored. How likely is it that bored teenager would get into trouble? Nah, never happens. 
Would he realize that the half-stoned hooker that taps on his window really doesn’t think he’s cute until after he realizes his wallet is missing?
Would he know enough to just drive away from the group of drunk frat boys, one of which is doing his darndest to pick a fight with him?
Would he know that the one really hot looking hooker is really a cop? Would he know enough not to antagonize the other cops when they show up to ask why he was talking to her?
Would he be able to keep his cool and help you home when you returned so smashed that you puked all over the side of your truck?