Having been audited over the independant vs. employee issue by the state of california, as well as enduring an irs audit focused on my music income, I can offer a few opinions based on my experience:
1. A bandleader could be deemed an employer depending on both the amount of control he exercises over his band members and also the activities of the bandmembers themselves. The issue is control-are they truly independant contractors who are in business for themselves and do work for others or are they exclusive to one band whose leader directs the way and times they are required to work? IOW, if you supply the instrument, tell the person where and when to show up, provide charts which they are required to follow, and they don't work for anyone else, they are likely an employee.
If they do other gigs, supply their own gear, and sometimes turn down your gig, they are independant.
As far as self employment tax, I've paid it many years. If you make a profit, you are likely going to have to pay it. A mileage log is no big deal if you keep records of the where and when of every gig. I use quicken for my personal finances and rarely pay for anything in cash. That way all expenses are easily tracked. I even deduct the miles used to go buy music stuff, as well as cd's , concerts, lessons, etc. My type of music doesn't require much gear, so I'm usually in the black. But even then the IRS tried to classify my income as hobby income. My accountant convinced them otherwise based on the amount of activity-lots of gigs. My accountant told me it is the intention of making a profit that makes the difference, and yet, when I asked him to represent me in the audit(highly recommend) he was pleased that I had declared a profit for the years being audited. Having a plan as to when and how your going to be in the black can't hurt............

Originally Posted by
SpaceNorman
I hadn't really thought about that angle. One of the things that struck me as I was researching the IRS and state publications on this issue is how virtually everything I read is written to preclude anybody from drawing a certain conclusion on how the rules would be interpretted. Were a case like the one you outlined to be litigated - I certainly wouldn't want to bet on the outcome. I certainly wouldn't want to be the bandleader in that situation either. I have no reason to think that such a scenario wouldn't turn into a "no good deed goes unpunished" for a bandleader unlucky enough to be caught up in such a suit. You've definitely given me (and probably lots of other guys who wear a "band leader" hat) food for thought with that hypothetical scenario.