On the other hand, it would keep the amateurs who play for free on 'open mic' nights because they would have to pay to play.
So who knows if it would balance out with more gigs?
Nobody is going to open mic nights to avoid paying for music. In my experience the crowd, if you can call it that, at open mics is about 10% regulars who could care less and 90% the open mic performers. You are just not losing gigs to folks having a little fun at open mics.
I must respectfully disagree.
Here in South Florida venues that used to hire bands now hold open mic nights on Friday and Saturday nights. Since they used to pay musicians on those nights, it does take food out of the mouths of working musicians.
Sure the musicians are going there to have a little fun, but the club owner is saving hundreds of dollars by not paying them.
The owner gets paid, the bartenders gets paid, the wait staff gets paid, the cook (if there is one) gets paid, ASCAP gets paid, and even the people who scrub the toilets get paid. In the club owner's eyes, these people are worth more than the musicians.
And the musicians are agreeing that they are worth less than the person who cleans the toilets.
Plus the musicians bring their friends along who buy drinks and/or food so the club owner makes even more money by exploiting musicians who want to have fun.
You can't blame the club owner: free entertainment that brings their own business. I can blame the musicians though for allowing this to happen.
Most of the 'open mic' musicians have day jobs. How would you like it if someone came in to work one day a week on your job for free, and your boss gave you the day off and docked your pay for that day? That is essentially what you are doing to a fellow musician when you play for free in a for-profit establishment