Without intelligence to drive this "cutoff" circuit, you'd simply be limiting your pulling power for the 99.99% of the time there is no problem with the electronics. I guess I'm not willing to do that. If you limit the voltage so a bare engine would not derail, having half a dozen passenger cars would result in a very sluggish consist.
If I really was concerned about this issue, I'd simply use a remote control button on a lanyard around my neck that could simply remove track power. This solves it for all locomotives and doesn't require I take apart and modify 30-40 locomotives.
I've seen tremendous push-back about a suggesting of adding a TVS across the pickups of the locomotives because it requires you open them up and do a simple mod. There's a mod that would probably be of greater benefit in protecting the engine electronics. I'm sure there'd be more push-back for a suggestion that actually compromises the performance of the locomotive to solve some very remote failure possibility and requires even more modification work.
Obviously, I'm not interested in doing this, but I have no problem with people coming up with a "solution", I just don't know there's a problem to solve.