I've been passing though a lot of airports recently, and -- by no coincidence -- I've been thirsty a lot recently. The simple reason for my thirst is the requirement that -- for our "security" -- I empty my water bottle at each security checkpoint.
Now most of you will be aware of this requirement, but perhaps not as many of you have thought of the incentives created by the no liquids rules.
First, there is the massive increase in demand for liquids on the other side of security. Although most people will buy bottles of water, some will buy bottles of sugary drinks -- perhaps because they'd rather get some sugar if they are going to pay $2 for 250ml of liquid.
Second, there is phenomenon of "missing" drinking fountains. In the old days, fountains were installed next to toilets, but there is less reason to install them now. That's because so many vendors are selling bottled water, and so many people are used to buying that water.
Note the insidious set of incentives that are operating. The airport managers can save money by installing fewer fountains because people can buy water; the vendors can sell more water because there are fewer fountains (supply) and more people without water (demand); worst of all, the airport managers can charge more rent to vendors because they are selling more water. Who pays? The travellers! This is an example of monopoly (airport manager) taking advantage of the customer -- selling less water for more money. (The same thing has been happening in schools where school administrators have been abusing their monopoly to sell more water -- and soda -- to kids with few outside alternatives.)
Oh, but remember that you are safer from water terrorists -- but not guys with knives.
Third, there's the warm water in the sinks in bathrooms. Although I am sure that this is meant to provide a better "customer experience," my devilish side says that warm water prevents "customers" from filling their own bottles. My environmentalist side says that we are wasting energy for very little gain in happiness.
Fourth, note the baptists and bootleggers dynamics that will maintain the ban on carrying water past security. The TSA (baptists) claim they are keeping us safe; the water companies, vendors and airport authorities (bootleggers) are happy to profit from this "security."
Bottom Line: The costs of the ban on liquids are falling on customers; the benefits are falling on airports, vendors and bottled water companies. With these incentives -- and lobbying realities -- we are unlikely to ever see a return to the good old days (allowing people to carry water). I guess that the terrorists have won :(