Similar to the 'live' feature in Halo, when you vote for a map if there is no maplist, there should be an option to 'veto' it, if you don't like it. If there are enough vetos like 3/4's of the players in the pub, the map with the second largest votes should play. To make this possible, there has to be a 5-10 second countdown until you can't vote for a map anymore. Then the map name should show up and another countdown could start, counting down to when you can't veto a map anymore.
thanks