What we did in our BCT15X / BCD996XT / BC346XT / BCD396XT is add a "user stupid" mode. Ok, we don't really call it that, it is actually called "Key Safe Mode." If you press/hold the main control knob while turning on the scanner, it toggles this mode on/off. When on, the user can turn on/off SQKs (like scan lists, but better), but cannot access the menu or permanently lock anything out (temporary lockout is allowed). Had this mode been activated, your issue would likely have not occurred (or at least it would have just been a matter of hitting the right SQKs to re-enable the desired systems set).
It also has the advantage of being available today and not at some dreamed of and distant future.