My only experiences of situations like this one are ferrets and photography (post 9/11).
Ferrets are banned in NYC, so if you own one before the ban, you can keep him (in fact, pet stores sells food, deodorants, shampoos, etc) but you cannot buy or bring a ferret.
Regarding photography, there are laws which most of the times are misunderstood and police officers dont have a clue. For example, you are allowed to use a tripod in the street and you can take pictures of whatever you want if is visible from a public place
many cops tell you not to use the tripod even if you show them the code! And sometimes, dont dare to take pictures of certain buildings
So
if they ban the e-cigs, as usual, you wont be able to buy them in NY (what will happen with business is yet to be seen), then we will keep on buying from other states or overseas and most certainly, they will amend the law and wont allow USPS or any other carriers to deliver within the state as what happen with the cigarettes (hopefully some vendors wont mark the packages and we will be able to keep doing the transactions). A nasty cop could arrest you if you use one in public or just for possession; but my guess is that they wont even look for it
so perhaps it will be better if your PV looks like a normal cigarette.
Think twice about analogs in NY
per code, they cannot be shipped in the state, but funny, some Indian reservations can send you them via USPS in unmarked packages while other vendors cant do it.
They will go towards the route giving them more money; I wouldnt be surprised if they simply treat the VPs as analogs taxing them as high and controlling the sales which will give them the same income and in that moment, they will welcome the e-cig and magically change their minds and think theyre great and healthy just as the analogs.