I come from sailing too (
Patrick), and whenever I would undo something that I wanted to make sure was "re-did" before getting underway, I would put a certain, bright "scunchi" type ponytail holder on the tiller to remind me (or anyone else) that there was something important to do before moving.
So I think if I undid the "umbilical" I might want to put something like that on the shifter of the TV, or someplace else obvious. Granted, you should check the rig always before leaving, but it's just a reminder since the wiring hookup is not as obvious as the tongue jack or the like.
As I found out when I first got a hitch put on my car, the "bulb out" light
on my dash lights
up whenever the trailer wiring is in use (if lights
are on, or a blinker, or brakes
depressed). This is because it uses a sensor that tells it to light
up when there is any imbalance in loads. I would have needed some more wiring done to correct it. But, after driving with it for a week or so, I found that I like it that way. I always know if my trailer wiring is hooked up or not, which has come in handy. And the dash light
is not a distracting, bright one.