1947's The Perils of Pauline is an example of the failure of the original copyright holder to renew the film's copyright and what can happen. Because the copyright wasn't renewed, this resulted in it falling into public domain, meaning that virtually anyone could duplicate and sell a VHS/DVD copy of the film. Legally. Therefore, many of the versions of this film available on the market are either severely (and usually badly) edited and/or of extremely poor quality since they were second- or third-generation (or more) copies of the film. Stay tuned!
What a shame.
Good thing we have Robocop