Revelers mark alcohol ban on London subway system , cause chaos . Police say at least 17 arrests , subways stations shut as thousands gather . Many had learnt of the event through social networking Web sites . Comment:
Revelers mark alcohol ban on London subway system , cause chaos . Police say at least 17 arrests , subways stations shut as thousands gather . Many had learnt of the event through social networking Web sites . London mayor says he introduced alcohol ban for better traveling environment .