Factual error: The oil "drill" is actually an oil rig, meant to pump oil, not drill for it.
Factual error: Facing the mysterious fighter from Africa in his apartment, Shaft shoots him twice with no results. It is later revealed that he was wearing a bulletproof vest, but it's the overpowered movie kind: the guy doesn't suffer from the impact of the bullet in the slightest. Not just that: there's not a single hole or mark on his white robe in that scene. (00:08:40)
Factual error: When Olive is repeatedly saying "I can't find it," Mr and Mrs Briggs are listening through the walls of their bedroom. However, we can see when Jack and Stan return with the toilet that Mr and Mrs Briggs are staying in the chalet to the right of the Butlers. When Stan first shows the family their chalet, it shows that their bedrooms are on the left. This means they wouldn't have been able to listen to Arthur and Olive through the wall.