setting plaf

Why is the plaf attribute only honored if you're not running on a mac?

Now, I can't claim to have actually tried to see what happens when you 
set a non-mac look and feel when running on a mac but, assuming it 
would work, shouldn't the option be there?

I'd definitely want it as there are some I'd like to use. For ex the 
Napkin plaf would be very useful when showing early stage apps to 
clients.
http://napkinlaf.sourceforge.net/


-Kate