A tidbit in 27 May issue of the Mac Treasure Tracing Club discusses a possible work around to the limitation in the DVD region code switching on the PowerBook G3 Series:

1. Play a Region 1 Disk.
2. Insert a Region 2 Disk, and dismiss the “Wrong region, you can switch up to 4 times” message.
3. Shut down the PB and do a system reset via “ctrl-shift-fn-power”.
4. The Region 2 Disk should play without switching.