Well, in my case, I wasn't actually meaning it strictly. In other words, I was lumping polynomial in with exponential, and RFC12 feels polynomial to me. Warnings don't fall into the essential category, in my estimation. But if that's the case, it will be easy to add without having designed it in first, especially if we've designed in the proper hooks for the optimizers. Note that I'm discussing RFC12 here.
Taint checking at compile time provides a different set of issues.