Point of order: Late use had no effect on when your next FP was available. You could always get another FP once your window opened or after 2-hours (whichever was shorter) whether or not you had used the previous FP. Actually, that's still true. The only difference being that if you haven't used your current FP, it will now become invalid at the end of the window. Getting another FP is not tied to whether or not you use a previous FP. It's strictly a matter of waiting the alloted time before getting another.
Your comment reminds me that, on another thread, a possible next-gen system at US was being discussed. It looks like they're considering a system similar to Six Flags' "Flash Pass."