As far as weddings, I've been in several, and a best man at one. The whole thing is a sham of epic proportions.
Tell them it's squat day and save yourself the money/misery.
(At the wedding for which I served as best man, my buddy and his bride spent the entirety of the afternoon and evening fighting. In the limo ... at the park taking photos ... at the reception ... Nightmare. Within a year of the "happy nuptials", he porked some ditzy broad he knew from high school, years and years ago. In his car. Now he has two bratty-as-fuck boys with the wife and she's perpetually angry with him about everything.)