Yes. This is a thing. My BFF and I were talking and he was trying to make me feel better about my wedding and he told me to search "Les Mis wedding flash mobs" on YouTube and a bunch pop up! And it is always the same song. Now I'm not really a big fan of flash mobs at weddings anyway but to pick a song from one of the saddest musicals ever is not cool. The last thing you want to think about at a wedding is dead destitute prostitutes and failed revolutions. Anyway here is one of the videos at popped up.