Well, I have pressed Shift-E, Shift-W, Shift-A, Shift-D and Shift-Q many times when I actually wanted to press Shift-S. I have never accidentily quit a character however, because I know about the danger.
It happened to somebody else today, so I thought it might be a good idea, but obviously it interferes with the roll-scumming program. I did not realize that, sorry.
Can't you just change the roll-scummer.