I just heard about this, one of my buddies was telling a "story" (not confirmed) about a guy that was driving his stock Vette on a course and it ended up being low on oil.
GM would not waranty his Vette because they found out that he had the engine over 6000 rpms for more than 3 seconds.
Apparently the "engine abuse code" was stored in the ECM
Is this folklore or is there some merit to it?

Can't say that I have ever heard of that before.

Sounds like a black box.

I wouldn't doubt it, anyway they can keep track of abuse to get out of a warranty.