Paleophil.. on the internet, you too can be anyone! haha
But no, my wife and I have never kept what we do a 'secret'.
I told my family straight up from day one what we were doing, (one) because its interesting, and (two) (and probably the real reason) was so that if we started to die horribly, at least somebody knew what we were doing. Since we 'look great' and stuff they know its obviously not detrimental (except for parasites, which we have had a few times) But after the initial excitement of the diet, i have learned to not talk food with other people (unless they obviously want to).
When you suggest that somebodys current diet is not the 'best', then you're pretty much saying they are !WRONG! and thats when it all goes downhill.
I always make sure to say 'hey, this is just whats working for me, its not the ONLY diet, since people are obviously thriving on all kinds of diets, if yours is working for you then it sounds like you're doing pretty good." Whereas before id try give them the 'facts' about why they are !WRONG!, nobody wants to listen to that person.
First day at our new job, my wife and I whip out our 'pirate lunchboxes' (just raw meat and some spice and codliver oil) and have lunch with everybody. After the few usual questions we're back to doing what we were before. Its no big deal to them, i guess because its no big deal to us, we're just having lunch.
Everyone i get my meat from knows as well, since everyone always ask(ed) 'how do you cook it?' and I just say 'I dont'. And they're not about to argue with their best customer.. haha.
I think one of my butchers said a few weeks ago that they were skeptical at first, but almost 3 years later we're still going strong and she said 'yeah i dont think its weird anymore, i guess i just got used to it', since im always in there telling them the meat inspector is a bitch because she wont let me have the brains, and how to leave the adrenal glands in the fat for me when they take it out.. haha.
Another reason we're just up front is because people always offer you food/drinks, and when you just always shoot them down with no explanation they might think you're being a dick. Instead they say 'Id offer you a sangwitch, but you would probably prefer some like... raw sausage or something! haha!'.
I dont know, mabye we just have a good attitude.. like if you're insecure about your diet people can tell? i dont know.
*edit*
Or mabye its just because my wife and I did this together, whereas most people seem to be doing it solo and their partner still eats whatever. So when you have two people doing it it helps make you more sure, and secure in/of what you're doing?