There is no block-off for nighttime EMH at Epcot. That EMH is actually 7 to 10 since Futureworld attractions usually shut down at 7. At 10 WS is actually still open for wondering around it (people are still in restaurants at that time). Perhaps what you saw was the morning EMH -- nothing in WS opens before 11 but you can still enter and leave through International Gateway (you just can't go in anything in WS and they block-off from International Gateway around to Mexico -- the other direction, i.e., heading toward American Pavilion, not the lane leading to Futureworld).