While still attached. >:D The sheer evil of RL-equipped trailers must be played to be believed. Its one of the most EVIL things you can do with a vehicle, particularly a normally helpless but fast ground vehicle, which becomes a portable fire-support vehicle until it has to abandon its trailers (or more likely, alpha-strikes you with everything on the trailers in one round).
I can't remember, but I don't think hovers can pull wheeled trailers, can they? Because that SM-1 of the Nova Cats would be perfect. Turning a corner and expecting a vehicle, probably a LRM carrier, and find an AC/20 with 10-20 RL-10 staring back at you...