There could be exceptions,big money shows etc.. but being a sub is usually more work, then what the regular player has to do. I am very clear about my expectations of pay and only sub if I'm getting what the normal player would get. I got a sub in my old cover band and he was making about 500$ a gig, for about a month and a half, played 8 gigs I believe. He was so stoked, when I returned he called me to hang as we often do, he brought a few hundred in thanks for the gig, I just let him take me out to lunch. To each his own I suppose.
I'll call you next time a need a sub Jimmy, will you take 125$ for the gig?? lol JK Buddy
Back to the subject, honestly if bar tending is more important to this girl, than creating future gig opportunities for the Cats, she doesn't sound like someone I'd want in my band, especially if we were trying to grow our fan base and places to gig. In my book she wouldn't even have the right to be offended if you get a sub or even a new drummer.
Sounds like the person obsessed with being a team (which is good on the whole) needs to realize that this drummer is making to many things a priority over the team, i.e.... not being a good team mate..