To add to my confusion there is a note about how to delete such files [CON, PRN, AUX, CLOCK$, NUL, A:-Z: , COM1, LPT1, LPT2, LPT3, COM2, COM3, COM4] under NT, so it must be possible for them to exist. It recomends (I love this) rm from the posix tools.
Presumably the permissions angle would be handled the way BP suggests.
GL.
Cheers,
Scott.