Even there, the code already records how the code behaves. The question is always which of those behaviors are intentional, meaningful. I am unable to fathom the utility of recording an arbitrary slice of behaviors, because those are very likely to be orthogonal or even contrary to the actual intent of the system. For example, every bug is part of how the code actually behaves.

I would much rather inherit a code base with zero tests than ones automatically generated by people who "just don't want to write tests".