Top 10% GW > Bottom 50% at Cornell and maybe a few candidates at GW would beat out some top 40% at Cornell considering that all those top 40% wouldn't have law review or moot court under their belts. I'm just trying to offer some food for thought.
Sure, top of GW will beat out bottom of Cornell (or any other T14). Putting that line-drawing aside, though, this is a dangerous assumption to make. It's risky to assume you'll do well at a "worse" school since you were accepted to a "better" one. It often doesn't work that way.