I do both, sometimes i let them repair, sometimes i dont.
Bit like in Mercs, sometimes i would not shoot at a mech thats shutdown on overheat, sometimes i did.
If the person is obviously new to the game, and my points wont really suffer from cutting them some slack for the sake of enjoying the game, then i do so.
If they are on the other hand handing me my head on a plate, then its no mercy asked and none given.