> Or people could just learn to use the search system?

Just like people should learn to use the search system before posting a thread? Or people should learn the ToS before participating in chat?

Obviously you cannot rely on users to do the right thing. If you're going to make some rules or guidelines, you'd better have some way to enforce them.

My suggestion won't totally prevent duplicate games. However, it provides an automated solution that is relatively simple to implement. It's not a "moderators should check for every uploaded game". A game would only have to be manually approved if the calculated CRC matches the CRC of another game already on Nonoba. This should be relatively rare except in the case of a duplicate game.