I say call their bluff. The market will eventually sort it out. If any ISPs do switch to use-based pricing, I expect their competitors could easily steal cust

I say call their bluff. The market will eventually sort it out. If any ISPs do switch to use-based pricing, I expect their competitors could easily steal customers by offering a flat rate. We might even discover there's a market for both options. (Of course, this requires competition, which is a definite problem in some areas.)