I want it so no one can accidentally turn them off.
I tried the LOCK but it doesn't lock the software limit button.
Use screen designer, and save a copy of the screens. Delete the softlimits button. In Mach3, make sure the softlimits are on, then use View>load screens, and switch to the screens without the softlimits button. If you need to turn them off, just switch back to the original screens.
Mach3 2010 Screenset
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)