What can we say? Thats China for you, they'll stall as long as they can before giving any explanations. not only re Tibet.

On May 6, 2011, the Chinese Government closed access to Everest Base Camp in Tibet.
Our trekking group travelled from Lhasa to Shigatse, to reach the police security check just before EBC (probably our 10th police check). We were told EBC was closed due to a landslide and would be closed for at least another 10 days. Our luggage was completely searched. We stayed at Tingri that night where we were positioned for a 6 day camping trek to EBC with full crew. Police were positioned at all access points and we were told we would not be given access.
We had to scramble to make alternate arrangements to go to Nepal and change our trek to a week there. (we couldn't do base camp from there as it requires 12-14 days.) We later heard Tibet EBC was likely closed due to political reasons. We left 6am on May 7th as we didn't want to lose any days of our vacation waiting around.
It sounds like it may have opened the very next day! Does anyone have any further information?