Same thing just happened to me. When the new band got together 3 months ago, the first thing I did was stress to everyone to email each other the dates that they would not be available for gigs, even if it was just a possibillity. That evening I emailed everyone the dates I wouldn't be available, and over the next two rehearsals I drove home once again we need to be sure we know who's available when so we can nail down gigs.
So, no mention from anyone about 4th of July. So I book this huge annual 4th of July party at the lake house of this oil-rich guy in my little home town. These parties usually draw anywhere from 500 to 1000+ people. I got him to agree to $250 a man plus the tip jar. Last year at this party a lame-ass DJ made over $1200 in the tip jar. Plus there's all these other rich f's at the party that have parties themselves, so there's definitely well-paying gigs to come from it.
So I get it it all set up and email all the details to my band mates. Seems no problem. 5 days later, get an email from the guitarist to the effect of, "Yeah, well, we usually get together with my girlfriend's family on the 4th so their kids can come swim in the pool. I've been trying to get out of it but it's causing too much tension so I can't make the gig". This is girlfriend, not wife. This is girlfriend's family's kids, not his or hers, they have none. I hate to just throw p-whipped around, as we all know there are times when the whip comes down, even on the best of us. But Holy Christ! That's EXACTLY what I was asking for from the beginning! Let each other know what dates you're even possibly not going to be available for!!!! AAARRRRGGGHHHH!!!!
So anyway, my name is S in my own hometown right now over this, and I'm out a fun 4th of July gig, and I'm out some pretty decent cash, and we're out some other sweet, easy, high-paying party gigs. No help to you, just using your thread for further ranting. Thanks.