One thing I learned from my "urban adventure" days: If you look like you belong there, you become invisible. Clipboards, hardhats, safety vests and the like all give a sense of credibility, as do fake cellphone conversations "What do you mean this is the spot? There's nothing here but brush! You'd better not be screwing with me or I'll..." or "yes i'm here, but I can't find your keys anywhere, ok, I'll keep looking" If you're at a park, nobody questions someone with a dog or a child about what they're doing off the trail or nosing around in bushes or whatever, particularly when said bushes are the recipient of a well-placed "wild" tennis ball toss. People do, however, notice if you look suspicious or out of place. Surveyors, building inspectors, tree inspectors (i love it) don't care who sees them doing their thing, and as long as they don't notice you specifically retreiving or replacing the cache there's little danger of them stumbling on it if its well hidden.
That being said, I prefer the direct approach: answer honestly when asked what you're doing, who knows, today's muggle could be tomorrow's cacher. Unless they see you in the act of fetching or hiding the cache you can always tell them about the activity and give them the website address, then depending on their response and what your instinct tells you about them either give them demonstration, or grumble something about entering the coordinates wrong and politely excuse yourself. I've converted a few this way, all fathers with youngish kids at various parks.. hand'em the gps, give them a brief instruction in how to use it if they need it, and send'em off to find that micro hidden in the sprinkler head. As I see it, they're less likely to come back and plunder a micro if my instincts are wrong about them so the risk is low, but its a good demonstration and if they honestly seem interested you can brag about some of your more interesting finds and send'em off to the website for coordinates. I guess its a judgement call based on your individual situation and feelings on the matter, but I personally see myself as an ambassador for the sport, doing what I can to promote it while at the same time watching out for the safety of the caches.
Just my two bits
Jeremy
