Scantronics
mordenstar.com
mordenstar.com
"Hauling off" is obviously just an exaggeration, but mechanical pencils worked fine with scantrons and that's what I used starting in 3rd or 4th grade (maybe earlier, that's the earliest I recall using mechanical pencils). The author is apparently unaware of the fact that "number 2" is a reference to the grade of the graphite and not to a specific non-mechanical pencil.
My elementary school specifically required Number 2 pencils on scantron related tests. And in the event that you didn't have one, a number 2 pencil would be provided.
I'll update the article to make it more clear!