So last year I was invited to a wedding (we'll call it AL wedding) at the same venue FI and I have chosen. The original location was printed on the invitations.
Since I had another wedding I'd already planned to attend that day (we'll call it AJ wedding), I responded that I couldn't make it to the AL wedding. My parents also were invited to the AL wedding and Mom RSVPed that she could and my dad couldn't.
So, several weeks before the AL wedding, I see in their engagement announcement in the paper (which i work for) that they're getting married at the bride's home and the reception is at a nearby country club. That didn't jibe with the invitation. We call MOB, oh, change of venue.
I tell Mom, she calls MOG and she says, "Oh, I thought MOB had contacted everyone about the location change." Supposedly she'd called everyone to let them know but my parents somehow missed out on that.
Apparently the original venue had been double booked and that's why the ceremony and reception had to be moved. We were assured this wouldn't happen to us when we booked there...in fact, the person responsible for the double booking had supposedly been fired as a result, and the venue owners paid for a pretty large chunk of the AL wedding to compensate for the error.
So I guess this brings up two WWYDs...
WWYD if you found out your venue had been double booked?
WWYD if your guests needed to be notified/if you were a guest who'd been left out of the loop?

