Dear All
Crazies has a bit of a reputation for this. Reg at WSP had a good idea - every time a car pulls into the Crazies carpark while you're rigging up, pull out a pen and write down their rego. Make a point of what you are doing (ie stand in front of their car while you write it down). If they are fellow sailors with nothing to hide, who would care ? If however they have thieving motives, they might think twice.
It's not the sort of place the general public would go in wet, windy conditions without a reason. If everyone keeps an eye out, eventually they'll get sprung. Hopefully by a fellow sailor, so they get an appropriate penalty, not a slap on the wrist in court........
Might not work every time, but I reckon it's worth a try.