I agree Dave . . . in certain cases and certain examples. For me it all boils down to a "gut check." If it appears as though the folks/muggles at a site might be curious about geocaching and are not the type to ruin the experience for others by taking the cache I'll often explain what I'm doing and why I'm there.
There have been other times however when the muggles didn't appear to be the type who would be all that interested and could lead to the cache going MIA. Probably a little bit of bias and prejudice on my part, but again for me it all comes down to my feeling as to whether the folks will be interested in geocaching or not.
For a long time now I openly geocache . . . there I've said it . . . I'm out of the closet . . . I'm a geocacher and I'm proud. In all seriousness in most cases when I'm searching for a cache I'll have my GPSr out and if folks approach me and ask what I'm doing I'll let them know . . . pretending that I've stopped in middle of nowhere to make a call on my "cell phone" gets to be a little ridiculous after awhile . . . besides I figure I may eventually get another person to geocache and I can't tell you the number of times folks have told me that they have a GPSr at home and are intrigued with the idea of geocaching.
This said . . . I do believe there are times to be stealthy and practice some commonsense. For example, I have a cache in middle of downtown Unity -- right next to a bank, telephone company, insurance company, town office, post office and paging company. Now Unity isn't exactly a hotbed of illegal and/or terrorist activity, but I've asked folks to try to be a bit stealthly so a) the cops aren't called on them as they wander to and fro (because quite frankly some folks would rather call 911 when they see suspicious activity rather than ask folks what they are doing) and b) while my match container isn't wicked expensive I did take some time to glue on super-magnets and I don't relish replacing this cache time after time.
"Courage is not the absence of fear, but the realization that there is something more important than fear."
"Death is only one of many ways to die."