Anonymous Twitter alternative developed for rioters

Riotters in London learned the fast way that pinging of twittering your actions also attracts police and other goverment agencies. The Register has news about a new app Vibe which makes it possible to send a message anonymously and for short a range around you. Much better, you can have it expire within minutes after sending and it will disappear without notice. Of course they still can track your mobile phone and which apps you use but proving you sended a particular message will not be easy. How long will it take before this app is banned from iTunes?