Baseballcap Effect
When something is done exactly how it should not be done, but the original goal is achieved anyway. Much like how wearing a baseballcap frontside-back will make your hair stick out of the hole and form a cover against the sun anyway.
That was the biggest baseballcap effect I have ever seen when the nurse was supposed to protect the kids from viruses, but ended up killing them all, but hey, the viruses will leave them alone.