I've always thought that turrets, buildings and vehicles should be able to be damaged by bullets tbh. The problem is the amount of damage I think they should do is so small (similar to what Security is proposing) that it really makes it pointless with the limited ammunition that players carry around. The way you could really deal with players shooting these things uselessly, is in the weapon selection have three sets of icons - one for infantry, one for structures, one for vehicles. If the weapon isn't effective against any type, you just put a big "no" symbol across it to denote that. Players will see that, go "makes sense" and then not use it for that. The only thing that really violates the rules is mini-buildables. What you could do however, is to make a bunch of things melee-able. I mean if someone's managed to close the distance to a structure, there's no point them being utterly useless while they're there. And let's face it, not everyone is always near someone else when there's a random turret in the way. If you melee a turret 15 times to destroy it, it's not really overkill and not too effective either. It's just something you can do to not be completely useless in a situation. Or you could give people a free spanner to whack things with. That would be fun. I remember fun, that was a thing that was part of gaming once upon a time.