Would it make any sense to add support for flags called something like
"+R" and "+W" that act a little like "+X"? I frequently find myself
needing to set make files writable by a group. However, sometimes some
of the files are not meant to be writable even by the owner. Therefore,
something like chmod -R g+W foo would make all files that are already
writable by the user or world writable by group.