My FILS are paying for it, so I realize I have no say and I really don't care, but I'm trying to save them some money by not inviting my extended family. We're having a semi-DW (4 hour drive for each family at a halfway point between the families), and FMIL wants to invite EVERYONE who is coming the night before the wedding. I always thought it was just those involved with the wedding and their dates/families. I have no idea what etiquette says on this, so lay it on me.