At least my experience with JFK is that you do not get hassled if your three ounce containers are not in a Kippie Bag. Most of the large airports tend to not care as long as everything is under three ounces. Unlike at SBA where the wannabe FBI agent started lecturing me that I was over a Kippie Bags worth and chucked some of them out (I'd bet my next paycheck they went home with him that night.)