Yeah that is how they test your shut-off switch they flip it off while it's running to make sure it shuts off. If it doesn't then it's pretty much useless. My 6AL is about 25 years old since I sent it to MSD when I bought it used to have them extend the wires and check it out. I am aware of how voltage spikes can damage electronic devices and I'm not saying it can't happen but tech inspectors do this to thousands of cars every weekend.

Gus

The MSD tech guy told me what kills them is reattaching the battery cable while running - if I recall he said it goes full field while disconnected then zaps the box when reconnected. I’m no electrical expert, still haven’t forgot my first electric shock.

Yep they check it the same over here too. The battery isolation (kill) switch should turn everything off and the engine should stop. Removing the battery cables while the engine is running will still allow the engine to run IF the alternator field circuit isn't interrupted. This can cause voltage spikes as the battery acts as a type of voltage "buffer".
I've had no issues with either an analogue 6AL or a Grid when the kill switch is checked but on the grid we do have a MSD filter (capacitor), which we also take the voltage supply for the Racepak from. This filters out any RFI or relay spikes though we've fitted flywheel diodes to the relays where possible.

So if your kill switch works properly, this won't be an issue.

Never had an issue, first started racing in '96 and they check it at least once every season. I'm always switching it on and off too but usually the car isn't running.

Let me re-state my earlier post.

Early MSD without full time +/- wires, engine RUNNING - disconnected the positive battery cable and reattached it and the engine stalled, could not relight it.

Checked for spark - none. Called MSD and the tech said I fried the MSD because of what I did. HE said I ended up full fielding the alternator and killed the box.

Sent the box in they said it could not be fixed.

This was probably in the late 90’s.

No clue if the newer boxes are protected because of the full time +/- wires and no clue if using a relay to use a kill switch would prevent this or not.