> "When an element's autofill field name is "off", the user agent should not remember the control's data, and should not offer past values to the user."

Seems pretty clear to me. The only exception I see is:

> "A user agent may allow the user to override an element's autofill field name, e.g. to change it from "off" to "on" to allow values to be remembered and prefilled despite the page author's objections, or to always "off", never remembering values."

But that's user-initiated action, not something the browser should do for every field just because it feels like it.