Fiddling with a tune simply means that the vehicle no longer complies with what the manufacture has documented with the government.
If you want to be technically correct, a tune would require recertification as has already been mentioned. A tuner sticking a sniffer up the tail pipe is not recertification as that requires a specific test process to be followed along with what I’d expect to be reams of docs and something likely being fixed to the vehicle to reflect this.
Having said that, I doubt any insurance company would care much if a claim was made unless you hit the newest performance Bugatti (around $8M I heard the other day) and what’s the probability of crashing into the one such vehicle in Aussie (if it ever comes here).
If you did slam into a Bugatti, your vehicle doesn’t need to run for the insurance company to be able to connect to the ecu and check if it is storing a non factory tune.
So, what’s the probability they’d bother with such tune checks in normal claims? Close to zero