So, as I see it, you're simply substituting "sneak mode" as your toggle. In sneak mode, you can steal. Out of sneak mode you cannot.
This is basically what I proposed, and have others, except the other proposals are, IMHO, better because they aren't convoluted with the sneak mechanic.
How is toggling sneak mode, any different than just toggling steal mode?
I just find sneaking and stealing to go naturally together. Make picking up items that others own possible when in sneak mode and make it impossible otherwise. Should solve the problem of accidental stealing without having to resort to popups or extra unneeded toggles/modes.
