I was thinking about a few ideas to help prevent bike 'loss', because I know that hoofing it from 9:30 to 2:30 sucks without a bike, sucks to do it a few times a day, sucks with blisters or playafoot, and sucks 10X if one had a bike and it disappeared. Most of this I read already on eplaya but just putting it out there.
1) Don't take anyone's bike without their express permission. I suspect that those to whom this applies are not reading this.
2) somewhere, label your bike with at least your Camp name and location after you get there. Either on the bike itself or with duct tape and a Sharpie. Doubt it would be delivered back, but thief may have harder time explaining to buddies why he has a bike labeled 'snagglepussy'. (Pronoun of 'he' used for demonstration purposes only here.)
3) buy a lock that does not require a key, but rather uses a combo. Easy to lose key, even though combo is easier to crack. I hear word combo locks are easier to crack code than #'s. Worst case scenario if the combo jams you can cut the lock. Lock front tire to bike frame itself, don't lock bike to art. Bike is unrideable without removal or herculean feats of wheelie-dom.
3.5) Lock your bike whenever you are away from it, portapotty, next to tent overnight, whatever. My camp mates had bikes taken from within our reasonably large camp, closer to Dawn.
4) Alternatively, I've read that some people are tying bungee cords or nicely tied rope around the tires/frame if you're going to be parked for a while. Makes it harder just to Grab & Go. Thief may move on to easier target, shitheads that they are.
4.5) I've read people suggesting to not bring bike to large gathering, as many bikes present, hard to find bike, easier for anonymous crime.
5) don't leave enticing things in your bike basket like full bottles of booze. Besides, you should be carrying this and drinking it.
6)

Just my 2¢. I hate when bad shit happens to good people.