
Often a problem at events, and not just weddings, lots of people, lots of motion, dark room, mixed lighting, high ceilings and nowhere to use bounce flash. Traditional approach is relatively fast shutter speed , perhaps dragging it a little to try and bring up the background (in this case
1/30) and keeping fingers crossed. Personally, I find this gets pretty lacklustre results, flashed out foreground (thanks for unwittingly demonstrating Alice!), dark background and "frozen" motion doesn't tell the story.
Been playing around with a really long dragged shutter (1 or 2 secs) and rear flash for the last few weddings I've been to, to see what effects I can get.

Might just be me, but I prefer the second approach - warmer, more dynamic, goes someway to actually showing what was going on in terms of motion and excitement, but rear flash rescues enough detail so you're not just seeing a mess of blur!
Interested to find out what you guys think.
(I've not touched the images, other than to save as JPGs by the way - I'd crop both tighter and I'm sure playing with D-lighting or similar on the first could help it)