To knock-off or not to knock-off?

I get a ton of emails from suspicious-sounding suppliers of golf equipment, usually from China, and they almost always say they carry the name-brand stuff: you know, Nike, Callaway, Ping, Titleist, etc. And they're kind of funny, too: plain-text, horrible grammar, bad spelling, and always from a guy named Mike or Larry or Simon (no last names given). I suppose, like anything, there's a big market for knock-off golf clubs. Do they perform as well as the real thing? Do people care, as long as it has the right logo on it? Well, the big players are taking it seriously, and have collaborated on cracking down on the knock-off trade. Here's the press release:
http://www.worldgolf.com/newswire/browse/58200-Criminal-prosecution-against-counterfeit-golf-club-warehouses

Just before Christmas, a lady came into our Pro Shop with a sleeve of Titleist ProV1 balls, and asked if they were genuine. Our Pro, Jay, only needed a few seconds to tell that they were counterfeit. Buyer beware.