I've said previously (other posts) and I say again, two GOOD reasons for having an isolator,,,
1) It will stop naughty people from attempting to cut your vehicle in half with your winch while you are sleeping etc.
(It only takes a bit of fiddling with a piece/s of wire to activate the winch via the control box if not protected by an isolator)
2) Winch solenoids have been known to jam on or stick, and an isolator can save ending up with things getting smashed.
Not so bad if your winching out at the time, but BAD if your winching in, especially if near the end of the pull.
For the above reasons, the isolator should be in a position that is normally inaccessible to "naughty people" ,,,,,,,, but also in a position that is easy and quick for yourself to access.
I always put mine under the bonnet which is pretty secure, yet easy for myself.
Its a good idea to always have the bonnet up when winching anyway,, to save the windscreen in case of snapped cable.
I do not fear death itself... Only its inopportune timing!
I've come to realize that,,,,, the two most loving, loyal, and trustworthy females in my entire life were both canines.