Thx to the vigilance of Grant Skinner, and to the tedious tests/debugging of probably many other developpers, the problem of "unloading SWF cleanly" is on the track of some sort of improvement.
Relevant links in historical order:
- AS3 ressource management part1
- AS3 ressource management part2
- AS3 ressource management part3
- Failure to Unload: Flash player 9's dirty secret
- UnloadAndStop in Flash Player 10
- Addtionnal information on Loader.unloadAndStop
It can be found here: Resource management for ActionScript 3 (AS3) and Flex 2 (the Janitor class is in the ZIP file).