Personally I probably make my judgements based on age or profession, but I usually don't give it much of a thought when I see someone wearing a gen.
If I did.. it only would be that, for instance I see a 22 yr old climb out of 90's economy car wearing DSSD, my thoughts are going to be rep. Profession wise.. car salesmen, gamblers, dealers etc..I will be thinking possibly reps. Other than that..I agree with Ronin, the majority that are out there that I see are genuine.
Until I found the rep community a couple years ago (I lurked awhile before I joined the forums) when I thought of a fake watch, it meant canal street Rolex to me. I had no idea the level of reproduction that was going on.
I have been into reproductions of things for a very long time, and when I found this community I felt right at home.