While you're modifying the step.rc, instead of turning it off another method might be to change the configuration it so that an actual click is necessary in that hotspot.
I've been using the 'tenebrae' theme and that's what it does; admittedly in this case only for showing/hiding bars, but the idea could be applied to other themes.
Though it is possible that a click in the corner of the map would still bring it up, I can't really think of a game that needs actually-in-the-corner clicks.

Something I'm going to try for a theme I'm working on: Many modern themes have a button that hides the bars... perhaps one can also disable the hotspots while the bars are hidden? Worth a try.