My thoughts mirror what Freddy333 said above.
I walk that fine line from time to time. If I were wearing my Ronin-1680 that is ALL GEN except the Yuki mid-case, I would never confess it to be less than genuine (just like I would never say a car is less genuine because it had some aftermarket body panels, after an accident). I tend to lead the conversation with, "actually, I restored this watch, it is a hobby of mine", and see where it goes. Usually nowhere.
On the other hand, if I were wearing my DW/Spin/Ronin Daytona or PAM 029 (as good as it is), I would come clean about their replica origin-- if the vibe and person were right.
People who immediately jump up and confess their Rep actually freak me out sometimes. It is as if they are so conscience and thus self-conscience about it they try and take the-- "I'm frugal, ha ha ha, don't judge me, I'm the class clown" approach.
Finally, on the RARE occasion these situations actually come up, I try and drop subtle hints. "Are you into watches, are you on ANY watch forums, Have you heard of the H/Noob/WM9-Factory?". To date, nobody has responded to those hints, and instead got the deer in the headlight expression. If they don't respond/know, I am not going to confess, and instead change the subject.
YMMV