I'm really not even sure how I would react in this situation. There's nothing worse than having to confront your dear sweet-old grand mother after a debaucherous night of fun. The biggest part of the FU in this situation was probably assuming that your older relatives wouldn't be up and starting their day at the crack of dawn. No surprise that they're already partway through their day when you decide to get out of bed.
Nothing better than an awkward family encounter to cap off a wedding.