Jonny, the vast majority of people at LM will look out for your gear and could be trusted. As with everywhere there is a very small contigent of theives, generally french "Pikies" who specifically target the campsites, especially directly after the race when allot of the gate security simply disapear. Camping Blue is a particular risk as it is open to the road, although we stayed there in 2003 without any or nowing of any problems.
In general LM is one of the friendlest places you could visit and people will be better pleased having a laugh and a beer with you.
