Yeah, I've been warned a lot despite never having done it on purpose, which is fine as otherwise it might not be effective. However, and I'll explain why this might be an issue, I've even received the final warning once when people kept running in front of me when I was shooting a rocket launcher at certain things a certain class can build. I haven't been locked yet though, thank goodness. My suggestion would be to make the reset timer on that go a bit faster because I'm warned all the time (which is not an issue) despite not doing it on purpose and it seems to take a while to reset and thus the warnings escalate fairly quickly. For example: I saw some dead NC infantry outside a thing that was being taken over. It turns out it was an NC guy taking it over but I didn't know that; he was at low health so when I popped around the corner and shot the first guy I saw I team-killed him, and received the warning despite apologizing to the poor fellow who was actually on my team. That was the start of the warnings; over an hour (it seemed to me, definitely not a scientific measurement) and I think one auto-logout due to a desperate and sudden need to go poo later I then inadvertently shot a few people with a rocket who were popping out of cover in front of me to shoot with their rifles as I mentioned above. After maybe two of those and being warned with increasingly threatening messages I received a message that said it was the final warning so with a bit of irritation I began to play much more conservatively out of fear of weapons lock. I had never received the original message again so I think it must have built up over time and never declined so to speak.
Also occasionally I get warned even though I only hit the guy with a few bullets and don't kill them; and these things happen fairly often when a lot of people are around and you are in a firefight in this game.
Makes me think I sure hope the government never hands me a rifle and tells me to go fight; I'd feel terrible if I did that to a real person on my team who can't respawn. Or any person really. So don't start any wars you silly government or you'll make me feel bad for killing a fellow sentient irreversibly.
Also, yes the uncontrollable vehicle rollout is terrible. I would recommend to the devs to do the following: make two, or better three vehicle spawn points and alternate them as people spawn vehicles. Let's say 1 2 and 3 spawn points. Spawn 1 first at the far left, then 3 at the far right, then the middle one. Heck if that doesnt work go to 4 points. Also consider removing the uncontrolled bit though if necessary keep the forward momentum. I've had vehicles become caught within each other where one has to go forward and one backwards; I've had the tiny vehicle almost blow up from flipping from uncontrollably ramming into the rear of a big vehicle, I've had all kinds of traffic accidents from being catapulted forward, and of course I've run over lots of infantry from the same. To hear that someone was gun locked because of it horrifies me.
EDIT2: Also the tiny vehicle probably shouldn't blow up when it flips upside down. It's pretty silly and while it's hilarious now it's also kind of a pain in the ass. If you want maybe the driver could take some damage because he's exposed, maybe like all your shields or something then if it happens again it kills you since you are after all exposed on that one. The upside down explosion sort of makes sense on the big vehicles since otherwise they would be useless and eating system resources and possibly exploitable as a roadblock, but perhaps a delay like in the Grand Theft Auto games to give time to bail out would be in order instead of the instant kaboom. Granted it's really, really hard to flip a vehicle other than the little guy but when it does it's instant crew or in one case team death.
Finally I've been using the little vehicle with a gun on it, and I've been driving up stairs in bases with it. It's cool and I hope you still allow it. That said with the ease of flipping on stairs with that vehicle and the current explodability issues of it, it means a respawn unless I'm very, very careful.
On that: Stairs bro. I warned you.
Also I don't do it unless there are no teammates around because running over your team is not a fruitful endeavor. That said, running over a few vanu while they capture something upstairs would be extremely satisfying. I had squadmates congratulating me on for almost running them over while driving the little vehicle to a captureable place and the appropriate spot where squaddies had just cleared Vanu enemies off seconds previous to my arrival with a "You crazy bastard." At that I hopped off ashamed but then they said "No, no, don't get off. That's a good weapon. Good idea."