How to duplicate a file with the same file permissions

While teaching the new 10.8 Support Essentials course today, a student asked me an interesting question about the duplicate feature in OS X.
When you secondary click on a file in OS X, one of the options listed is “Duplicate”. However if you then hold down the shift and option (alt) keys, the Duplicate option changes to “Duplicate Exactly”.

duplicate exactly

Now surely a duplicate is already an exact duplicate?
Well not exactly, after doing some research online, I stumbled across the following article on TUAW.
It seems that “Duplicate” will duplicate a file and save the permissions but “Duplicate Exactly” will retain the file ownership as well as permissions.
An interesting 10.7/10.8 feature I hadn’t seen previously and I’m sure many others have not seen either.