The old FAT filesystem, still used by many USB mass storage devices like my new USB key drive, does not have a good concept of permissions. That is: not even as good a concept as UNIX. It's common that the default behavior when mounting a FAT filesystem on unix is to set everything a+rwx. I'd rather not have files mounted a+x, so normally I could set a mask in my fstab options. On OS X, though an automounter is used that doesn't seem to be configurable on a per-filesystem-type level.
Is there no good way to reduce the maximum mode of a FAT filesystem's files?