…and Gary Lineker gives you crisps instead. That’s what bemused commuters in Clapham and Oxford Street must have been thinking since last Thursday, when special Walkers vending machines were installed at three busy bus stops. These are not your average vending machines though – Walkers have grabbed attention with a ‘Tweet to Eat’ system that neatly allows passers-by free crisps at the same time as ticking the social media box.

We went to look for the Walkers Bus Stop nearest our London office, but despite faithfully following the directions we were left crispless. Thanks a lot, Gary.

But it does seem that others have had some luck with the machines, with the @Walkers_busstop account receiving a fair bit of attention.

Of course, the power of social media has led to the campaign being talked about far beyond its London-centric borders, with coverage on countless blogs (sorry) and even national newspapers.

With this kind of attention online, does it really matter if the bus stops themselves have technical issues or are missing completely? Only if you’re a hungry Oxford Street shopper expecting a free lunch.

For experiential campaigns with a social media element, where should the focus lie? The truth is you only need a few retweeted words of praise for the campaign to be deemed a success. The flipside is that just a few grumpy tweeters can be your downfall. But when it comes to the crunch, it seems Gary Lineker is a pretty safe bet.