Yep, knife manufacturers are weird, too. I guess they have to be.
A case of box cutters we got recently at work warned: "This cutting utensil provides no applicable safety features when the blade is fully extended."
I guess not extending the blade fully is an optional safety feature. We got the retractable blades because one of the guys cut his thumb to the bone opening a box a couple of weeks ago with a new blade in one of those single-edge razor blade handles. Cutting across your body is always likely to cut you. Some people already know this.