See this post for links to articles on how the UK has passed special custom-written laws that effectively say that free speech doesn't apply to the Olympics, the London Olympic Committee can tell you what words you can use (not just trademarks), and how London is being turned into an armed camp for the duration.
My annoyance with this is not inconsistent with my role as chairman of WSFS's Mark Protection Committee, which tries to keep people from misusing "Worldcon," "Hugo Award," etc. WSFS doesn't care if you use those terms to refer to the actual convention or the awards presented by WSFS. Indeed, we like you doing so. We like it when cities consider it worthwhile to put up banners at the airport or on the streets welcoming our convention to town. We only get annoyed when conventions that aren't the World Science Fiction Convention describe themselves as "Worldcon" or when people give out awards that are confused with the Hugo Awards. (Both of these things have happened and continue to happen.) What the London Olympic Committee is doing is radically above and beyond simple trademark protection.
With luck, they won't decide that having the military occupying the city isn't a good long-term idea. If I lived in London, I would have been long since been trying to figure out how to be out of the city — preferably out of the country — for the games this summer. My sympathies go out to flick, drplokta, and my other friends who live in around London, who it appears may be prisoners in their own homes for a month or so this year.