I think Walter gave a very good argument for why it's the biggest mistake, and no warning will help with the consequences that he pointed out. That C has UBE i

I think Walter gave a very good argument for why it's the biggest mistake, and no warning will help with the consequences that he pointed out. That C has UBE is not a mistake, it's fundamental to the language design, which allows for unrestricted access to the bare metal. If you want a different sort of language, use Java.