I'd go along with this if it'd get people to stop putting/asking for 87 for their vehicles that are clearly 89/93.
The other day I had a customer asked if it was alright to get 87 for her 89 grade vehicle. I answered, "It's best to go by what the car's owner manual says." I went on to explain that putting lower grade gas runs the risk of engine knock on top of worse things.
