Yes, and its not wise to stay in a prolonged fight when your in a vehicle with relatively thin armor. IMO, its like a little warning light saying "Hey, you're pushing it, might wana RTB next kill".
Honestly, I think the reason HTC hasn't added some, along with more tanks, is that most of the players yell for "more important" additions, such as AC or a reworked damage modle.
IMO, if we had more vehicles, a lot more people would GV, and we would see GV's taking a more important role in the MA's.