In case this is ever "fixed" a hole still exists in xpdf as well (you need to get it through DarwinPorts or the like).

Open it up, print to file, and -- unlike doing the same thing in Preview -- the ps file it produces can be easily converted right back to an unprotected pdf file.

I don't know postscript at all, but since it's just text I assume you could edit the ps file produced by Preview yourself to unprotect it. As long as that exists, it seems that Adobe is going to have a hard time with their DRM-like permissions.

Yes, you can unprotect the postscript file: Open it in your Text Editor, then search for "mark currentfile eexec". Delete this line down to "cleartomark" and replace it with "cg_md begin". Then you can open it in Preview and you have an unprotected PDF.

This of course requires that you are allowed to print the PDF. And because PostScript printers must be able to interpret the code, its just a command recoginzed only by Distiller and other PDF-generating applications that tells 'em that they must not create a PDF.

The way via ColorSync Utility doesn't seem to work in Mac OS X 10.5 anymore.