People got arrested on Cannibal Holocaust because the Italian government thought they were killing people not animals. They were cleared of all charges when they proved it was just movie effects. Ultimately this wasn't a crime either.

Animal safety laws were a lot more lax prior to the 90s. Apocalypse Now has a real cow killed and Heavens Gate killed something like 5 horses. It was in the late 80s when the American Humane society stepped in and started enforcing this.