> A prevalance of spurious warnings tend to mask real ones, by teaching
> people to ignore warnings. So I'd like to get rid of these one way or
> another---but preferably without sprinking with-no-warnings all over the
> place.
Once we're sure that the remaining calls to toggle-read-only are all
"correct", we should try to understand why that is and provide some
alternative function for that (and make toggle-read-only use that
function, of course).