Dustin, I can't see the vid you posted. It's probably flash or something. iPad sucks. Anyways, if you can post a link I'll check it out.
As with any move/technique, there's always a counter. One shouldn't rely on lockdown to work 100% of the time.
Your opponent will have short legs, will have repped escaping, will be more aggresive, or will be able to slip through(sweat = less friction). Just know they may know how to get through, so anticipate and react first if possible.
Talk soon man.