I noticed bots stuck trying to shoot a mob stuck in a tree. They were there for the hours that I was playing the game and I thought that if you didn’t do this on purpose, it would be a great bot filter. You would figure that anyone who spent more than 2 minutes shooting at it before realizing that it wasn’t taking damage has to be a bot. Using this or a similar mechanic, it should be easy to create bot traps.
Making these bait mobs take occasional damage would make it hard to re-bot around.