I am assuming that Tosca is an opera piece. if correct I imagine the musos and singers are reading from music. I also imagine that if it is opera it will cost a few bob to go see it. a singaround is mostly keen amateurs. and I guess that they wont be to sad to see the elitist performers go off and start their own club. it might be as well for any elitist club to say upfront, at the door, that only star quality is allowed !
I hear that a by invitation festival this year was a bit of a flop.
maybe no one applied, lest they be turned down !.