I see what you're saying. I haven't had my stylus set up in its default mode since I first got it. I have my stylus buttons set to "step back and step forward" in the history (essentially undo/redo). I guess if I set it back to default your suggestion would be very handy indeed, though to be honest, overcoming the now ingrained twitch response to use those buttons as undo/redo would be more trouble than it's worth, but thanks. I'm sure this will be handy to a lot of other people.
I have some issues with the autohotkey script you posted, Palomar.
At the beginning, it works half the time, then, it tends to not working at all.
Instead of that, the stamp tool is still working ( S hotkey ).