Whats wrong with plates?

Had a very nice sandwich before seeing a film tonight, but i dont know why it was served on a chopping board rather than a plate. There are several campaigns on this topic; a google search for 'we want plates' will find you the 13 worst things restaurants have used instead of plates, a 'we want plates' campaign and a @wewantplates twitter account. Who would have guessed people would find it so annoying!