The problem is that at open() time, there's no good way to specify what the
expected label is (now *that* might be an interesting extention to open() for
some enterprisng grad student) - so as long as the file has *any* foo_t label
that the program is allowed to access, the open() will succeed. There's no way
for it to say "I'm opening what *should* be a locale_t file, so if I'm being
coerced into opening a user_foo_t, please nuke the request".