If John pays Martha to do a job, then John should file a form 1099-Misc. However, there's got to be a minimum below which the form is not filed. We do not, for example, inform the IRS every time we pay a teenager to babysit for an evening.

At casinos, I believe the minimum is $2000. I doubt if any house concert ever paid anything like that.

If I were holding house concerts, I would find out what that minimum is, then keep a simple record of the take for each concert and where it went. If questions are raised, I would have the answers.