So if you hire the Girl and her bf is the only one she'll fuck... can you just pay the girl her rate and not pay the guy? Afterall, they are a package deal.

It depends on the couple. The going rate for a b/g scene if you hire a girl is $800 (some girls charge more)
The going rate for guys varies too....
So, typically a couple will want at least $1,000.
And to me that sounds fair if the girl is hot and the guy can indeed perform.

I guess its too bad you can't get "surety bond" on performers, in case they don't show, can't get wood or whatever.

Man, I hate that couple shit. Same motherfuckers OVER and OVER!