Accidental use of "/" in file names

I accidentally used a "/" in a filename (I know it's invalid), but came up with some interesting results. The file was on a USB attached drive. On the Mac that had the attached drive I could see the filename. I have two MacBooks that are network attached via wi-fi to the drive via a share on the attached Mac, and on one of them I could see the filename, and on the other I couldn't. Once I dropped the "/" it became visible to the one that couldn't see it.

Anyone have any suggestions why one MacBook could see it and the other couldn't?

Using 10.6.7 version on all machines.

 

All my drives are formatted OS X Extended (Journaled).

The Mac with the attached drive DOES have parallels, but the MacBook with Parallels was the one with the problem! The MacBook WITHOUT Parallels could see the file.

This all occurred in Finder. The problem is academic, but I think it's an interesting problem. Thanks for your reply.