Choking bands at the bottom will force him to use speed to blast though the tension. Yes, the tension will increase more as he goes up, but the tension for the entire lift is higher too. One of the reasons you leave the chain long enough to touch the floor is that it will provide resistance from the very start, and never totally let off. Reverse band deads, even though they train the lockout, force you to take advantage of speed off the floor so that you DON'T get stuck when the bands let off.
In otherwords, we don't just use AR for lockouts.