Hide and Seek is my favourite minigame on this server. However after playing each map a few times, it's gets easy to remember where the better or more obvious hiding places are. For example, the places where there is a single block missing in a section of the same block, like a hole in the gravel in Mines or a missing block in the stack of bookcases in Library. What I suggest is to make something that will randomise this missing block places so no-one will be able to memorise where these hiding places are. This could probably be done just with redstone rather than needing an extra plugin. A random selector could activate different command blocks to replace a block with air, each time a map is loaded.