As a halfway measure, it would at least be good if the core warned you: "This version of Tiger requires jAlbum version 22, which is newer than the version you have. Should I install the skin update anyway?"
The automatic skin upgrade should be guaranteed to improve the user's experience. We don't want to offer an upgrade that may cause problems.
If a user wants to experiment with an incompatible version of Tiger, he can manually download the version(s) that interest him. The typical (i.e. ill-informed) user should not be enticed into a bad choice.