I can't find anything about VCR's blocking; I did find a bunch saying the opposite.
There were copy protections that prevented a VHS -> VHS copy being made of some movies. Easily defeated, but they did exist.
My scenario was recording an Over The Air transmission onto VHS using a VCR; not making a backup copy of a movie you purchased on VHS.
Edit: I do recall a campaign against VHS recording of TV shows, but didn't it ended basically saying "Broadcast public == public domain"?. That actually led to copy protections in VHS tapes.