I did indeed know about the fact that Devel::Trace does not contain a license when I posted my response to Moron (see my reply two posts up err, one post lower)

everything else he has said in this subthread is aimed only at modules in a similar state of "no licence attached"

No, almost everything else is aimed at modules licensed under a FLOSS license. But I never mention that one needs to contact the author again (indeed I specifically denied that this needs to happen).

the general feel is that "You cannot use free software without the copyright owners permission--even if thay haven't added an explicit copyright notice"

No, correct would be "You cannot use a piece of software (writing, music, etc.) without the author's permission if they have not added an explicit license." If a piece of software is licensed under a FLOSS license, the author has already given you the permission to use it, it's in the license.