a good deterent
this happened to me at work at least twice in the same day.
It was a saturday, which meant no one called in with problems an basically you had 4-6 hours of free time. So i had the three 3e core rulebooks out on my desk, characters sheets, and notes for a module. First, this lady comes over who was dubbed "chatty kathy" because she just loved to talk and not being a morning person I had no tolerance for this. Anyway, she comes over says and is just about to start conversing when she looks at the open books and says what's that so I close the PHB and show her the cover..."oh," she says, "well I leave you alone." That was the last time she ever tried to start up a conversation with me.
A few hours later a guy who just likes to tell you everything about his calls comes over and again looks around doesn't ask anything, gives an an abbreviated description of his call and leaves me alone for quite some time.
In 90% of the times I had my books at work, everyone looked at the covers and left before any explaination was asked for or given. Upon reflection, I don't think any one in the office was a gamer. I worked with people older than me mid-thirties and up. I was the youngest at 22-27.
I guess it all depends on where you work. my rpg stuff isolated me, which I was thankful for most of the time. And I never had to answer the answerable, "what is that?"