Great responses so far.
Context, age, and where you are located are all key.
In my geographic location: Gen's are everywhere.
My Age is greater than 35: By this stage in life, most anyone could afford/own/buy a Gen
So, nope. I think I am passed being asked the question. Although,many friends I have handed GEN Rolex's to, that knew they were Gen, all
responded with "I thought it would have been heavier and going by feel would have thought it to be fake!" (Gen Stainless, Hollow Mid's)
Finally, the "It's a Rolex, it must be fake" is so statistically inaccurate that comment just shows ignorance IMHO. Rolex produces around 700,000 watches a year, and there are roughly 40,000 members of the Rep Community. About 1 in 6 Rolex's in the wild is probably fake. A betting man would bet on Gen.