No, no, you're quite correct in saying that they are permitted. However, they are not permitted in Parts Library files, and I wouldn't be surprised if a similar restriction applied to OMR files for the same reason: the files need to be cross-platform compatible.
Parts Library files are restricted to a-z, A-Z, 0-9, _ and . (plus \ or / for s\ and 48\ names, of course). I would expect OMR files to be the same, although I don't think this is stated in the spec (yet).
Parts Library files are restricted to a-z, A-Z, 0-9, _ and . (plus \ or / for s\ and 48\ names, of course). I would expect OMR files to be the same, although I don't think this is stated in the spec (yet).