I'm an active local musician/electric bass player and I have a group of musicians I call in 1st, 2nd, and 3rd order for gigs. I have a drummer who is first call. I bring him a lot of gigs, judging by the size of his 1099 at the end of the year.
Anyway, he called me a while ago asking if I would mind if for a couple gigs at a restaurant not far from him, if he could use our piano player (2nd call guy) and a string bass player for the gig. His reason for this was the owner "wants string bass" and I'm an electric player. I said fine, but indicated that if I was going to call him first for all the gigs I have, I'm expecting to be part of the gigs if the instrumentation is the same (piano, bass, drums) that he books.
Personally, it irks me when I bring musicians a lot of work, find the musicians, arrange the rehearsals, get everyone music, and then they go off on their own, when there are no apparent interpersonal skill or other problems. I also think the owners' string bass requirement was hokus.
I later see all over the Internet that he has named the trio, and gotten a professional video done. He is listed as the contact for this group, and they are doing music festivals around town.
How would you proceed with this case?