The cost of power
I would hate it if this happend, but it wouldn't surprise me. Pay for Power. Attache some type of payment system to power outlets in public places so that in order to get juice to recharge your laptop, cell phone, music player, etc.. you have to pay. Obviously the rates would be different depending on where you are. For example, a coffee shop might be $1/hour while an airport might be $1/15min. I can understand how some businesses would want to make sure that they are compensated for a higher electric bill, but I'll be it becomes impossible for them to resist the temptation to turn this into a profit center. Smart businesses will realize that they will get more customers for there primary business if they don't do this, but there are a bunch of companies that aren't that smart.