Came here to post this very thought. Collision + body metal cutting through the hot line insulation = full battery amps until exhausted. Yikes.
I've got a marine on/off switch (Blue Sea E-series, 500 amp) on a homemade bracket. It sits about 8" from the battery under the hood. I leave it off until I need the winch. Raise the hood, flip the switch and winch away. Nice piece of mind and cost me about $50 total.
One other concern for ya'll. Back in the 80's jackalopes would freespool the line out, throw it over the top of the vehicle (or under it) and fasten to the trailer hitch. Then stick a paperclip in the proper holes and walk away. You can guess the result... It was pretty rare, but I saw it happen personally in a high school parking lot. Granted, this was in the days of the three-pin controller, but you could still do it with a five pin if you were really determined.
Yet another reason to have the cutoff under the hood, protected by a Bolt hood lock - as mine is.
Food for thought...