They might not realize they're hurting themselves, which makes it a bug. Backblaze did this with one of these hash collisions. You could back up two different (

They might not realize they're hurting themselves, which makes it a bug. Backblaze did this with one of these hash collisions. You could back up two different (colliding) files and when you tried to restore both, only two copies of the same file would be returned, the other one apparently lost forever. Why would you have colliding files? Perhaps because you're somebody working on hash collisions and have collected some examples.