Restrict the repair tool to vehicles not moving

My preferred solution would be to disable the repair tool while in the passenger seat.

Some alternatives would be to reduce the repair rate by something like half or halve the amount of time it takes for the tool to overheat while in the passenger seat. And this may be in the game already, but each repair tool active should have a diminishing return when repairing the same vehicle so the first operates at normal efficiency but the second operates at 50%, the third at 25%....

I don't like any of the calls for the reduction in offensive transport capability. I'm fond of the idea that, in the right circumstances, the transport helicopters acts as sort of a discount AC - 130. The problem is that with two repair tool equipped passengers you can sponge damage to a ridiculous extent. Couple that with Charlie's repair boost and things go from absurd to insane really fast.

Damage negation (repairing) is something that needs to be really carefully regulated and the general rule in a *representative realism* military shooter is that you want to lean heavily in favor damage output over negation, lest things become unintuitive. Damage negation should be largely confined to a separate phase: You want to have as little crossover as possible to minimize situations where you are outputting damage while simultaneously negating incoming damage. 

*representative realism is VERY different from realism. It's designed to introduce mechanics the represent, not simulate, battlefield activities. A good example is the revive mechanic: You do a little revive animation to represent providing medical aid to a wounded comrade.