Water water everywhere

Ok, so I see conspiracies everywhere. Maybe it's because I've read one too many Tom Clancy novel, or maybe, just maybe it's because they actually exist everywhere? Maybe Mel Gibson was on to something (no, not with the religion/drinking!)?

Take my last trip to the airport, two weeks back. Because of the British binary liquid event two months back, passengers are no longer allowed to bring liquids on a plane (I mean bottles of water, juice, etc, not shampoo and such). Perhaps it's unreasonable, perhaps it's not, I don't know. But what I'm disturbed/baffled by is the seemingly idiotic way it's being implemented.

At the airport, while hanging out in the non-secure area, there are shops where one can buy beverages - coffee, water, wine even. Anything purchases outside the secure area must be either consumed or discarded before going into the secure area. Not too unreasonable.

But then, in the secure area, they sell more beverages! And you can buy them, and wander around the secure area with them, etc. But anything purchases must be consumed or discared before boarding the plane.

That makes no sense at all! What is different between the bottle of water I buy outside the secure area and inside? Nothing at all near as I can tell. And yet, I can't bring a bottle from the outside inside. So what's the point? Why can't I buy water outside the secure area and bring it into the secure area?

Is this some sort of plan devised by the vendors inside the secure area to sell more liquids? Maybe at a higher price? Of course it would cost more, it's secure; just like a Kosher chicken costs more because it's been raised right and blessed?