The map room protocol is the fun part of meetings between the Dalai Lama and any given US president. One day the Dala Lama gets up with an irresistable urge to go to a room and look at maps, whereupon it is pointed out to him that the White House has such a facility. While there, he encounters the President, who has contracted the same urgent cartographic impulse. I think this is the third time Obama and the DL have had such a happy encounter.
Anyway, China protests yadda yadda, but no big deal; as it never is. After all, the whole map room thing is staged partly to accommodate Chinese sensibilities while making clear that the Prez can meet with anyone he wants. Obama also specifically endorsed the DL's autonomist stance on Tibet for the first time, which incidentally allowed him to re-state that US policy sees Tibet as part of China, which in turn puts China in an interesting position.
Anyway, contrast this smooth piece of policy jigsaw execution with Cameron firstly making it clear that he'd meet the DL precisely to tweak China's nose, then when China responds in an entirely predictable, even traditoional, fashion, caving in completely. There was, incidentally, no reason why Cameron couldn't have carried on meeting the DL if he wanted to: there were no consequences for British contact in China other than Chinese officials refusing to meet him or members of the government for a bit longer than a year. But that meant he couldn't put himself out in front of whatever deals were being done and claim credit for them and so the head had to hit the pavement. I kind of hope Beijing will find some other pretext for pulling his plonker, but they don't have Putin's sense of humour over there.