Exposed Mayweather? <__<..By landing some jabs? The same jabs people have been saying are the key to beating Mayweather if he's ever beat (outside of a shocking one punch KO, of course).
Anyway, I don't think he's very text book. He's just so economical and even though like someone said, he "exposes" his chin when he throws, bear in mind how infrequent he's ever been countered by something threatening when he throws. When he throws, he knows he's most likely landing. Like someone said, we don't see what he sees. Hindsight is 20-20. Floyd does keep his hands up though much more than given credit for. He does a lot of things almost "perfect" but it's because of his reflexes. He's slowed down a tad, but his instincts are insane and his reflexes aren't down right gone or anything that severe. There's a reason you see guys who are freakishly gifted (athletically) not do as well as Floyd..-cough- Zab - cough-. It's his IQ and instincts.