Can we add a feature to the debugger to add a breakpoint when a watched value / expression changes?

I've a DEU* who managed to find a way to change a pointer that she shouldn't be changing, and it's hard to follow how she did it. I'd like to make the debugger hit a breakpoint / raise an exception when that value changes.

*Defective End User. Usually present when PEBCAK (Problem exists between chair and keyboard)