As a newbie, could you enlighten me - is this some kind of special secret sign shared between cachers?
At the moment, if I see someone who I think is a fellow cacher, I usually ask if they're looking for something. If they smile and say yes, we then have a nice chat about caching experiences. If they look at me blankly I surreptitiously put my GPS in my pocket and wish them a pleasant day. Hopefully they won't notice that I have bits of hedge stuck to me as I walk past them.