aww, that's frustrating, atleast my parents booked (I don't know if it cause I am only child) I am sure your mom will book, she is probably waiting last minute, like the FI's parents. (they aren't involved in the wedding at all, very sad since the SIL got married in Aug and they were very much involved)
I'm at a point, I don't really care if anyone comes anymore besides my parents and of course the FI, I feel like if our family and friends really cared, even if they can't come they would have rsvp'd, to even just show some respect.