There's some attempted gaming of the Steward badge visible in the Review / Close Votes history on SO.
If you look at the top reviewers for the day you can see the gaming clearly: there's a small group of users who have double the number of reviews of the 'true' leaders.
Looking at the review history, I'd expect to see Close/Do Not Close (DNC) appear somewhat randomly. If most initial flags are correct — which seems likely — then there should be more Closes than DNCs in the history, rather than an equal number.
The majority of reviewers do indeed choose Close much more often than DNC. But a few have a noticeably higher proportion of DNCs. Also, some people appear to use up most of their Closes, then switch to mostly DNCs. I spot checked a few of these 'late' DNCs and many seemed unlikely to be 'correct'.
Trying to achieve badges is not a bad thing, but in this case each incorrect DNC increases the chance of a post with problems leaving the queue before it has been fixed.
Can something be done to make reviewers treat each item in the queue fairly, regardless of their badge target?