Has anyone ever actually had insurance not pay out for mods?

[Acuity30]

Purely out of curiosity, no I don't have any undeclared mods on my own car. However I've read many times of people saying if you were in an accident, particularly an at fault claim, with an undeclared remapped motor, the insurers can take the car away, have it dynoed and void your insurance.
Well, has this ever happened to anyone? Or other things like not declaring aftermarket alloys, or debadging/rebadging etc. What difference do those make in the grand scheme?

[DaveH23]

https://www.pistonheads.com/gassing/topic.asp?h=0&...