That's still a very striking omission of a feature.
Lambda isn't available in all zones, and not everyone has the time/ability/knowledge to set up such a thing. I'm sure I could do it, but only if I were to spend a few hours researching it, and probably a few nights working on such a solution. I'd also have to trust that I didn't mess it up -- I'd hate to have a bunch of traffic and NOT properly prevent the traffic.
This is the kind of thing that Amazon surely could provide easily if they wanted to.
It's like if your phone company didn't give you an option to limit your spending (prepaid), but said that you could use their arcane API to tell them each month to start/stop service. That's great, but not really very nice to customers.
