Personally, for that one, I'm gonna be doing the 'pull the lanyard and listen for magnet humm' test (with disconnect switch OFF as well as ON) before connection of the trailer to my TV.
It's just too easy (and IMO prudent) to verify that situation beyond any shadow of a doubt with the actual trailer of interest
before each tow, settling any possible whimsy or error by ETI's wiring-technician-du-jour or later system fault.
It matters not one-iota to me what the behavior is on anyone else's trailer, YMMV