In CW3, downloaded community maps could be played when offline. I don't seem to be able to do the same with PF (linux, not steam).
This fix is in the next version to be built. Turns out there was a little bug (one missing "&") in the exchange code and the entire exchanged functioned only accidentally.
http://knucklecracker.com/forums/index.php?topic=21687.0
QuoteDONE: Ensure the exchange works when there is no network connection (show cached results).