In either C or C++, should I check pointer parameters against NULL/nullptr?

This question was inspired by this answer. I've always been of the philosophy that the callee is never responsible when the caller does something stupid, like passing of invalid parameters. I have arrived at this conclusion for several reasons, but perhaps the most important one comes from this article: Everything not defined is undefined. If a function doesn't say in it's docs that it's valid to pass `nullptr`, then you damn well better not be passing `nullptr` to that function. I don't think it's the responsibility of the callee to deal with such things. However, I know there are going to be some who disagree with me. I'm curious whether or not I should be checking for these things, and why.