Wow, this is really, really lame. Sorry for your misfortune. Your friend's friends can't reschedule the wedding ? Makes sense that they do this though. They are trying to avoid scalpers with the presales. If they allowed you to do this, just about anyone could buy presale tickets then turn around and sell them on Ebay and change the name on the will call. The rule is awesome, how it affected you is not. I hope in the end you guys are able to figure something out. Is the wedding actually at night? Because to hit a wedding during the day and skip the reception at night for a NIN show, that does not seem too rude unless you are part of it(also depends on who's wedding it is too). I would talk to your friend and figure out where the priority really is. Figure out your time window as fr as when the wedding is vs. the concert.