Heard a rumor from a friend of mine that works at WDW that the monorail is going to not be working for Extra Magic Hours. He said he isn't 100% sure but it would cut some operation costs. He said that he could only see the MK area guests being hurt by this that are at the Poly and Grand.
Makes sense to me, since I walk a lot of the time when at the Contemporary. And its easy to take the ferry to the TTC and walk to the Poly. If they could to the walkway to the Grand (difficulty with the canal for the Water Pageant's holding area, but could do a bridge like they have at Epcot between China and the outpost).
Edit: 7/12/2011- Local news just picked up this story. They said that WDW released a statement that this was because of the aging system and repeated breakdowns, that this will provide longer repair and maintenance time overnight to keep them running.
