Is there a setting that will "warn about the outdated .elc,
and then load the more-current .el", so you realize you have
an issue? You're a lot more likely to re-byte-compile the
offender if you actually know it's an offender....
Or does the proposed setting do that?
It depends on how you define "warn". This setting causes a message to be
issued of the form
Loading foo.el ... (foo.elc is out-of-date)
But it doesn't use the `warn' mechanism, which would cause the *Warnings*
buffer to be displayed,
With a more obvious warning appearing.