Checking on something that has puzzled me for some time.
If you turn off the salesman's switch while being plugged into shore power is your batteries(chassis and house) still being kept charged?
I presume your inverter still works fine and the salesman switch does not shut off the fridge but what about everything else?
Speaking from my experience with my unit only. Inverter charges house batteries even with salesman switch off. My chassis batteries are charged by a Battery Tender plugged into the block heater outlet and so those stay charged as well. Salesman switch does not shut off the fridge, the CO/propane/smoke detectors, radio memory or the aux air compressor. There may be other things that I'm not aware of.
No reason to be puzzled.
For any given coach year/model, to determine what is controlled by the salesman switch, simply refer to the B-2126 wiring diagram. Everything downstream from the switch is dead when the switch is opened.
See example diagram (found in our excellent Forum Library) linked below:
https://www.foreforums.com/index.php?action=media;sa=media;in=3297