I don't think a fan watching on TV can determine without a doubt whether a low blow is intentional or not. In the heat of battle, a lot of blows go south of the border in many fights. Don't forget that Vargas went low also, and on several occasions. Tito just kept fighting... didn't make a show of it.

The only low blow I've seen that I know was deliberate? Zab Judah aiming at Floyd Mayweather's nuts and then rabbit-punching him after that.