Going through our response cards and guest list, there's a huge hole -- no one from my mother-in-law's family has replied. Can I ask her to find out whether they're coming? They're her guests, after all -- it's not like I've ever met them.
Not to burst your bubble, but technically no matter who's doing the inviting (or the paying), it's still your wedding -- hence, they're your guests. If you hit your cutoff date for responses (which you should have set for no later than two weeks beforehand), pick up the phone and give them a gentle reminder -- the response card may just be in a pile of to-dos, or they may have misplaced it. It might even be a nice way to introduce yourself to some of these folks that are technically soon to be members of your family. However, if you make the effort and find you really can't get a hold of them, then it may be okay to ask your future mother-in-law to lend a hand. No matter what, you shouldn't assume they definitely are (or aren't) coming -- otherwise, you and your vendors would be headed for a head-count disaster.
Wedding Invitations + Wedding Stationery