This is intended to be a multiplayer experience plugin, because of this if only one person is on the server, they will be unable to see, move, place blocks, break blocks, eat or drink, until another player joins the server.
if there are two or more people on the server, the effects will disappear and both players will be able to play minecraft normally again.
ThePlayerShuffler will gather everyone's locations and headings every x seconds, where x can be configured in the plugins config.yml file. Once everyone's location has been gathered it will shuffle all players locations by teleporting them somewhere that another player was standing and facing.