Scanning password-protected files

Avast produces a list of files that cannot be scanned because they are
password protected archived. Most of these files seem to be part of
Ad-Aware SE and are .bump files. I would like to see Ad-Aware remove
the password protection because there is no point to it. However, I can
see an argument for making Avast (and other scanners?) skip protected
files but guarantee that they get checked when they are extracted from
the archive.