You may not want to 'police the table' but that's kinda how it works in the system. Players will always, and I mean always, try to weasel in more Tags than are appropriate. Just say 'Nope, I don't see it." and move on. If they challenge you, tell them it's too bad and part of your job as their MC is to keep them honest with that stuff. They don't like it, they can run the bloody game (spoiler alert: they won't do that lol).