U2's concert drawing power is gone.

250 Concert goers? U2 is done.......Wait. What? Unannounced concert appearance for charity? Never mind...............
Star Pulse:
U2 stars Bono and The Edge showed up unannounced and played as a warmup act at a charity concert in London.
The show delighted the 250 people who attended the fund raiser on Friday night for Mencap, a charity that campaigns for equal rights for children and adults with learning disabilities.
''Don't tell Larry (Mullen) and Adam (Clayton) we've done this,'' Bono joked about his other two band mates from the small stage at London's Union Chapel.
Bono and The Edge - performing as a warm-up act for Biffy Clyro, a Scottish rock group - played four of their songs: ''Stay,'' ''Desire,'' ''Angel Of Harlem'' and ''Wave Of Sorrow,'' a track written for their 1987 album Joshua Tree.
A member of the audience, Simon Dowling, 20, from Newcastle, northern England, said he was shocked when the U2 stars suddenly appeared on stage.
''I've used all the battery on my phone taking pictures of them,'' he said.