Please stop writing "Public Domain" for things which clearly aren't

Public Domain has a specific legal meaning, and a work needs to be placed in it by its author (or the copyright holder). Please don't put "Public Domain" in the Copyrights field for things which are clearly derived from commercial works. 

(most recently, several disks of Sam-converted 128k Spectrum games)

Whether I'll make them downloadable is a different question (to which the answer is usually yes) but I'd like to keep the actual legal paper-trails as correct as possible please.