Saturday night, GSP fought Carlos Condit and in the third round was hit with a beautiful head kick coming off a combination. He hit the floor, and the commentators, as they are prone to do, completely overreacted. It was a great kick, sure, put GSP in a bit of trouble and if Condit had stronger ground and pound he may have finished it right there. However, the kick did not make GSP's eyes glaze over, or him look close to being unconcious. As soon as he hit the ground, he was looking right at Condit and getting ready to defend.
In one of the main card fight, Cote vs Sakara, Cote caught Sakara with a shot. Instantly, whether because it had landed flush or because Sakara is known for a weaker chin I'm not sure, but the commentators insisted that Sakara was "hurt bad!" and "in trouble!"
These are not isolated incidents, as one of the first time I noticed was Silva vs Sonnen 1, where Chael caught Anderson with a good punch and Anderson stumbled. He was not rocked, he didn't look especially hurt, yet Rogan and Goldberg screamed, yet again, and as Anderson let Chael follow up with shots they repeatedly made it sound as if Anderson was anywhere close to going out.
To be honest, it shouldn't matter to me at all. But considering I am a fan watching the fights, I seem to get it right whether a fighter is actually rocked and can come back more than the (presumably) more knowledgeable commentators that are sitting right next to the cage.
To sum it up, being stumbled/knocked down does not instantly mean you are rocked and close to being KO'd.