Meh. For one ruined picture she has 10 great ones. Enough for the bride and groom to have great memories. I can't get worked up over that. Keeping your guests hostage (lol) so that you get a better choice of pictures is dumb. /gavel
I'm pretty sure most of the weddings I've been to have had "No flash photography" somewhere in the program. I might even be on board with a request thrown in there to be respectful of the professional photog and not get in his or her way.