One part of the internet/warranty story is true - some places do sell gear online that they are not authorized dealers for, typically from a manufacturer that doesn't allow online sales, and it won't have a manufacturers warranty (in the US at least.) In this case the shop will generally offer their own warranty. Something to be aware of, yes. Dangerous, no.
Typically these manufacturers set prices so you can get much lower prices by going the "unauthorized" route. For many people this works just fine. And for some, the policies of the manufacturer tick them off enough that they avoid those brands. The dangerous/counterfeit stories generally come from shops who resent competition from online retailers, and are often authorized retailers of the brands in question.
