How genuine is Green pledge on supermarket booze?

The "other" Councillor Little - that is, Stephen who represents Town Close for the Greens - had a rash of excellent press last week that included linking in with the EEN's campaing to support pubs by not buying alcohol in a supermarket for a year (click here for more). Great, you might think - but a click on a different web page makes the story a little less clear. Rather than being a personal crusade, according to pledgebank.com, Stephen writes that:

I will not buy alcohol from a supermarket for a year but only if 500 other people will do the same.
— Stephen Little, Green Party City Councillor

That isn't quite the same thing - and as only 19 people have signed up so far it might seem that Cllr Little is off the hook; so if this is more than just a publicity stunt, no doubt he will be making clear the pledge stands, even if 500 don't sign up...