I think the leaderboards are the issue. Maybe a pipe-dream, but it would be good to have a way to identify the experts for a taxon without encouraging this type of behaviour. In fact, I’ve found that many of the most knowledgeable people only have a few IDs, because they are usually only called in as pinch-hitters to ID the really tough or interesting ones, while some of the top identifiers have only ever agreed with others.