"Organise "flashmob folkies" to gather, totally unannounced, outside selected Sam Smith pubs and have an impromptu 10-minute chorus of uproarious songs before disappearing?"

Better still, do it outside Humphrey Smith's house in Towton, near Tadcaster. He lives in a bizarre world of his own and doesn't give a shit about his customers or his managers/staff. Personally I wouldn't be seen dead in a Sam Smiths' pub.