Ah, yes. Street musicians. I always take the opportunity to stop and listen - no matter what, and I always make a contribution. When I was at UMASS in 1975 (I had "tenyear" in college), a guitar player used to show up in the student union, He was from Boston and wore a badge #1 issued by the city of Boston (I guess to try to enforce some kind of bureaucracy on an the practice of singing - oh, what's next).
Another memory has me on a shuttle boat in Nassau. There was an older gentleman playing guitar and singing. Now, one of my favorite artists of all times is Joseph Spence who lived a good deal of his life in Nassau. During our conversation, this "boat" musician allowed as how Joseph's playing "just complexifies my mind." I later asked him to play a particular song (I was riding back and forth between the shuttle stops at this point - ain't no way I was leaving). His response was that that song just never grafted to his head.
Last October I was in Denver on business. Whenever I travel, I always seek out the local music scene. Ran into a street musician (can't remember his street) but he had been there for years - every day - winter and summer. Again, I stayed until "last call"
Except for one guy I saw playing Jethro Tull's Aqualung on an electric guitar through a Pignose amp (Boston), I would call all these buskers "folk musicians" - please see thread entitled Methodologies for more on this subject!