I'm not sure what the exact law is here, but I do know that my sister told me my nephew and niece couldn't ride in my Corvette until they were able to be out of their car seats and booster seats. I'm assuming the air bag had something to do with that, but I'm not positive.
Oh, and 2-seater cars FTW!
If nothing else, when there's more than 2 of us going to lunch, I don't have to drive.