Jeri, I draw the line at money. If you (or I) get paid, we are singing professionally, not folksingers. If we sing at the session afterwards, or from the floor, we are folksingers. I consider this applies to everyone, including professionals.
They are 'stars' when I buy their music. It is subjective, as far as I'm concerned.
Rhetorical questions answered while-you-wait, sometimes.