Dude, it'd never happen. Picking up grappling from instructionals and dvds with no prior grappling experience or actual mat time other than rolling around with the occassional friend at a drunken BBQ will not equal success in a match.
Picking up BJJ/judo/wrestling whatever strictly from instructionals is like someone learning the alphabet and expecting them to be able to write English fluently and read. You won't know ANYTHING about hip movement, flowing, transitioning, positioning, god you'd be missing out on so much.
Besides, for people who do actually have a lot of grappling experience, well I don't know about the rest of you guys, but many times whenever I look in books/magazines I find dozens of small details that have been left out.
You could take any redneck, teach him how to do a guillotine, and chances are he could maybe catch someone with it because it's such a simple submission to do, but what if it doesn't work? What if the guy does the counter, what if he escapes? His whole plan has gone to shit because he never had one, he never had a big picture, just various techniques he picked up from wherever the hell.