I used to work in claims i saw some monstor claims and never saw a car be combed like that to find out that you have mapped your ecu you could have to wack it on the reader which would be giving off all kinds of faults anyway if u had a life ending accident. I dnt see how you would ever get caught out on a map
i've been a claims adjuster for the 4th largest commercial insurer for the past 4 or so years so i've seen it happen.
i have my own case where a kid modded his bloody scooter on his dads fleet policy and managed to write a car off. we found out and refused insurance. he said he couldnt pay the 5 or so grand back so we took him to court and he's paying something like £20 a week back to us. i get a cheque in every week and it's a pain tbqh but serves the idiot right.
a colleague has another case circa 20k on a special personal lines policy where the kid was fronting with his dad as the main driver, he crashed, police came, he was all dazed e.t.c and said in his statement to the police 'oh i was just driving to work' we then had him interviewed and worked out his dad basically never drove it. refused insurance again on the basis he was fully aware he was defrauding the system.
but like i said 99% percent of the time you would get away with stuff like maps, it's the obvious like alloys, exh, inductions that you get picked up on.
all im saying is if there is a slight chance it could happen, which there is, i'd rather declare it than be found out and be poor for the rest of my life!