Ahh.. another church sound system guy. I did that for about 20 years until the church made it a staff position - was offered that but was not interested.
Before our church orchestra had built up, our choir director hired musicians from the local symphony to fill in the gaps. We used to record the choir concerts - nothing fancy, basically a house mix with a couple of ambience mics hung from the ceiling.
I was setting up the mics for the violins when one of the paid musicians asked if we were recording it. I said yes. At the end of the concert, a couple of them came to the back room where the recorder was and confiscated the tape, saying that the contract did not specify recording rights. We explained that the tape was for church archives only, but they left with a nice 10 1/2" reel.
That was certainly their right, I suppose, but it did leave a sour taste for those of us who had volunteered countless hours to put the concert togther.