Jesus, what a terrible idea. This is such a terrible idea that I would not hire this guy based on this post alone.

What I want from code is for it to a) work, and b) if that's not possible, to fail predictably and loudly.

Returning the wrong result is neither of the above. It doesn't draw attention to the deprecation warnings as OP intended--instead, it causes a mysterious and non-deterministic error, literally the worst kind of thing to debug. The idea that this is going to work out in any way calls into question the writer's judgment in general. Why on earth would you intentionally introduce the hardest kind of bug to debug into your codebase?