Definatley lock your bikes up. Four years ago we had about 14 bikes in our camp. A few people in our group didn't bother to lock up their bikes, and the next morning one of the bikes was gone. The worst part is, it was a 80th anniversery Schwinn that can never be replaced. BTW... I told them not to bring that bike and also told them to lock them up.
"She changed her mind when she couldn't change me..."
No matter what they say I've done, I ain't never had too much fun!
IMO I'd lock up anything you want to keep if it's left outside of your car/rig...cooler, bike...
Last year my BF locked his bike up and figured no one would take my old cruiser...well needless to say he was wrong on that one...We kept looking to see if someone just rode it to the venue entrance and left it but never found it. He ended up having to buy me a new ride which was ok with me