That may just be because they don't like you much, but it's more likely due to the recent arrival of foursquare in the UK.
Foursquare is an app that lets you digitally "check-in" wherever you are - telling your friends that you've arrived at The Ivy, or Starbucks, or wherever. There's an interesting rival service called Gowalla too; the really committed check-in to both.
This is obviously useful if you like to show off about your drinking and dining habits, or are trying really hard to accidentally bump into a new business contact. They also add an element of fun by awarding points and badges for each place you check-in, with extra points available for being first somewhere, or visiting lots of places in a day etc. Visit somewhere frequently enough and you get to be the "mayor" of that place. It's very silly, slightly pointless, highly social and therefore deeply compulsive.
Perhaps most significantly for we marketing folk, it's also the perfect platform for one of the great cliches of interactive/mobile design: the idea that you'll walk past a restaurant or coffee shop and get a discount voucher beamed to your mobile device. It's been tried a dozen different times and ways but none have ever been that satisfactory - there's not been a critical mass of people or sufficiently smooth technology.
Foursquare, however, might have the right platform to transform it from theoretical cliche to effective utility. I checked-in to Bar Bruno recently on Wardour Street (easily the best place for a cappuccino and bacon sandwich in Soho) and was told by foursquare that the Hummus Brothers restaurant up the road was offering a two-for-one deal on main meals to whoever was currently its mayor. It might be obvious, but it's also genius. It rewards loyalty, but in a playful, competitive way; it stretches out geographically, without the need for lots of fly-posting or leafleting; and it's relatively non-intrusive - it operates in a context where the offer makes sense. And, presumably, it's all administered by foursquare: no little cards need to get printed and the restaurant staff just need to have a look at someone's phone to check their mayoral status.
Mobile spam is one of the more annoying phenomena of the modern age, but I suspect things like these four-square promotions will prove more acceptable because they've built an appropriate social platform for the service, not just a technological one. So, have a look at foursquare, check-in somewhere and we can try to avoid each other around town.