Mach3 is the only controller I have ever seen that moves to safe Z if stop is commanded and it shouldn't IMO. What happens if your using a T-slot or keyhole cutter?
But, with Mach you have the flexibility to make it do almost anything you can imagine. All I ever want stop to do is stop motion. I will do everything else depending on the situation. Anything else is hazardous IMO but like opinions, machines vary drastically and in the right setting I could see additional actions being a good thing for the operator, tooling, machine, part, etc.
So, while we are on this subject, what do you think should happen when the stop button is pressed? What parameters would you want to look at (if any) to determine this action?