The only way we could know for sure is if the person who got that key came forward, and I'm not sure he or she'd even wanna do that with... [Well. Kurapika the cuckoo-clock]

But I mean, if there's a rule against giving a key to multiple people, or the person with the key passing it around if they feel like it... would htat be in the rulebook? Even Levi's explanation that he doesn't choose whose alignment he learns, that's in the rules if you squint real close at the buddy cop description compared to the detective one.