Unlike domains, parking communities is free, so there is no consequence for creating a community and abandoning it. If I ran a bot that automatically claimed the names of the largest Reddit subs on your instance and then abandoned them, should your instance shut down those communities for good? Taking communities from moderators can be opportunistic, but that's not a reason to close a community permanently because someone wanted to park the name or lost interest in running the community. Your problem with sniping would be solved if admins manually review the existing moderator and requester's contribution history to the community before handing it over instead of relying on a hard time limit like "6 months of inactivity". If the requester has no previous relationship to the community and seems to be a name sniper, their request is rejected.