Yes, they are grey market !
This is my understanding as well. If the warranty is important to you, go to an authorized reseller. Try a few and ask if they can discount the price, it never hurts to ask. The other day I was at one of the authorized dealers and one of the first things the salesman told me was that he could come down on the prices, I don't know how much because I was not looking for a Cartier watch.
I think most AD will come down on price at this point. I was in Saks on 5th Avenue last February and looking at a Cartier LaDona watch and the SA told me (without me asking) that they'd be able to come down on the price. I am thinking it was 10%. So my thought is if Saks is discounting then they all are.