Dale,
Sounds like you have done a great job of identifying the issue. A few suggestions come to mind:
1. Targeted assassination seems to be a popular technique these days and is quite effective.
2. If your provider is right-handed, arrange a fall on some ice (Michigan has lots of that, right?) onto his right arm. If these approaches seem too drastic, maybe just convince him to cast it. It sounds like he will no longer have this issue if he has to work left handed.
Sorry....sometimes my sarcasm gets the better of me. You can either reason with him or try to find a technical fix. It sounds like you have tried both, to no avail. Maybe some of the IT gurus here can help with a technical fix. On the reasoning side... instead of trying NOT to replicate his problem, try to replicate it. Hit the mouse repeatedly and try to freeze the program. If you can do this, sit him down and show him: "this is what you are doing to make it freeze. You see, it is under your control. Do you want to continue to have the freezes or not"?
