Now, just over a week in, here are a few from brands who are not officially associated with London 2012, but who are still trying to associate themselves in the public's minds with it. Incidentally I don't mean anything legal by 'Hijacking', it's just that in the perception of many they are using guerilla marketing to ambush or associate themselves with the event and the coverage.
The most obvious example, trading on the 'no, not *that* London' idea
Also, this one. Again, a different London:
Also talking about a different place called London
Talking about a celebration, and how they can't be any more specific
"It offered a 30% discount to anyone who visits its stores with products from non-Olympic sponsors.
To qualify, customers need to visit one of Oddbins' 35 branches wearing Nike trainers and have in their pocket a set of Vauxhall car keys, an RBS MasterCard, an iPhone, a bill from British Gas and a receipt for a Pepsi bought at KFC."
Trading on a certain sprinter's 'archer' victory stance
Trading on the Olympic flag mix-up in the first day
Ad in an email newsletter received by a colleague, and possibly less of a case of a hijack than someone not knowing the law
Beats by Dr Dre
They didn't advertise, but they did give nice headphones to athletes in the hope they'd use them on camera
Google isn't an official partner as far as I know, but they've been doing a series of doodles during the games, some playable, including Hurdles and Basketball
Not exactly a hijack, but they re-created key moments using LEGO bricks
Please let me know about any others in the comments!
Also - here are some other examples of ambush marketing from previous events.