> An inaccessible directory is empty for all intents and purposes

Not always; for example, (directory-files-and-attributes "/etc/news") signals an 
error if /etc/news is inaccessible, and returns nil if /etc/news is empty and 
accessible. However, your use case is yet another example of why the new checks 
are turning out to be too picky, so I reverted most of them (i.e., the ones 
having to do with file-readable-p and similar predicates) by installing the 
attached patch, which fixes the bug on my platform.

Thanks for reporting the problem.