They were all in a very good mood, as they walked on - very cheerful and smiling a lot. "Mike Mac" was grinning like a Cheshire cat. Either they'd got some very good news or they'd been imbibing. What - I'd hesitate to suggest.
There was a fair amount of smiling and laughing between the band members during the show and that's not too unusual but doing so at the very start was - to me, anyway.
It may have been that they had family or friends in the audience, as I saw "John Mac" looking out to one part of the venue and seeming to make a subtle signal at one point.