I don't know. My motors do fine with water in them. Some guy on RCgroups breaks in his new brushless motors by running them underwater! I don't know how it doesn't short, but I've flown in the rain (here we get quite a bit) before and still have the motor(the one I used on my Cabon B-1 scratchbuild)
I haven't bought it yet but it should work on everything. ESC, OSD, Servos, ect. It isn't oil based like WD-40 so it wont mess anything up. All I would be worried about would be dust and grim sticking to it.