Just went out and checked mine, and yes, even if I turn off the batt shut off switch in the basement I can still turn the level-up system on. Reason for this is as far as I can tell is that the systems in mine at least are direct wired to the batt, and power the module controller and then to the wall pad.
I would also assume it is designed that way to keep its memory, so that when you power it up to couple to the truck it will still remember your last height setting.
I am quite sure it is not to remember the level of the system, as I had all batts out and no power applied, and did not have to zero level the system when I reapplied the power.
Don't know for sure on that though.
I doubt that the small draw on the batts to keep the memory is enough to cause too much drain on the batts. My level up controller is in my locked basement, and I have previously instructed the kids and wife not to mess with it if unlocked for some reason, unless she is performing the extremely very rare occurrence of having to couple/uncouple the rig.
I would likely not add another switch for this as I think it is a little redundant with having the lock on the door, and the aforementioned memory issue.
As a side issue, if people messing with your coach is a common occurrence I might suggest camping or storing it in a better area if possible (kidding), as there are worse things that could happen than someone touching the levelers. JMO.
If the door with the level up system in it is not lockable, change out one of the latches for a keyed latch.
Congrats on your your new 5th Wheel.
2014 Voltage 3818 (Epic I & II)
2005 Fleetwood 31ASV BP Toy Hauler
2017 Ram 3500 Longhorn DRW, 4x4, 3.73, Aisin
4 Seat Long Travel Sand Rail, 97 Jeep TJ Rock Crawler, 68 Roadrunner, Various Quads