I get asked for car meets alot actually, I never do them though. I have thought about it when outcall business has been quiet (I generally only do outcalls) but I've never gone through with it.
If you are going to do it, just be very, very, very, very, very careful. Text a photo of the registration plate of the car to a friend, make sure they know the minute you are due back and to phone the police if they don't hear from you.
It's up to you, and plenty of girls do car meets and must be happy enough with it....but just remember, you won't literally die if you don't get that ?50 (or whatever). A car meet has a lot more potential to go wrong than an outcall. To me it's a whole different ball game.