I've never had a problem here, but I figured I'd contribute.
Here's the official word from EOTech:
http://www.eotechinc.com/counterfeit-alert-how-to-spot-a-fakeYou see these a lot at the gun shows being sold by the guy with the thousand really crappy NCStar scopes/optics.
I bought one of these fakes when I was younger and dumber, they are not really even worth the low price they sell for. I broke the one I got simply by pressing the buttons on it.