[dagw]

I can't recall the last time I saw a busker in a private space like a mall or airport.

While not buskers per se, a lot of private spaces hire musicians to play in their spaces to provide entertainment or background music. Many airports I've been to have someone on a piano playing in a corner

I've also seen places like trainstations where they have a licensing system. IE you audition, apply for a license and then get given a spot and a time slot when you can busk.