There is a geocacher here in Korea that has stirred up a lot of controversy recently by placing caches using their own account, then adopting it to another account, deleting the adoption log, and renaming the owner of the cache to the new account. Then he logs ftf. When he was caught, Groundspeak had him readopt all of those caches and then locked the other account. But then, he has now adopted those caches to a third account and archived them. In every instance he has deleted the adoption logs to cover his tracks and make it look like he didn't do anything. It's the second time he's done this in ten years sometimes adopting a cache 6 or 7 times before finally archiving it.
So I guess my real question is... Why can adoption logs be deleted in the first place? It seems like an important log akin to disabling or enabling a cache, logs which cannot be deleted. It just seems to me that allowing the deletion of adoption logs enables this type of cheating to be hidden from the community.