Brownie56, I think your concern is that if neighbor kids remove the pin, that the constant current to your brake magnets will run down your battery and/or damage your magnets; valid concerns. I leave my trailer on my driveway for several days at a time and there are lots of neighbor kids, but they don't seem interested in my trailer. That said, it could happen.
I believe that by design the break-away system is very simple. I don't think there is a fuse, or breaker, or switch. The only way you could deactivate it is by removing the connection at the battery.
The 30 amp fuse you have probably protects the wiring to your DC distribution box; the break-away system is separate.
Maybe you could attach the cable to the switch in such a a way that the cable is easily removable? It'd be tough for a small kid to grasp the plastic pin hard enough to remove it without the cable.
Whatever you do, make sure your break-away system is working when towing; if you need your break-away system, you really need it.
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch