Yes, as Ebbie says, it amy sometimes depend on the tour schedule: they have to be off as soon as the concert's over to go to the next place.
And as Leadfingers and other have suggested - it depends on the artist too. Some years ago, I spent a magical whole day in a pub session in Sidmouth in a session where Dougie Maclean played with whoever came in, the day after his big gig.
And much more recently, at Celtic Connections in Glasgow, we had Alasdair Fraser, Phil Cunningham, Kris Drever and many of the professionals playing into the wee small hours in a certain hotel bar with all comers great or small. Likewise the "House of Song" was a democratic mix of all comers, be they professionals or first-time-ever-in-public amateurs.