I would guess that it's not worth the effort, due to the risk of a physical process failing (lose painter's tape, need to make a copy for cutting, etc).
In modern practice, scan, bitmap paint 100% black, print?
In the very few documents I've had to redact (PII, not tyranny :P) I actually used white boxes instead of black to waste less toner, but yeah it's the same idea.
In modern practice, scan, bitmap paint 100% black, print?