I think that, like Jason Alexander, Michael Richards does a little spontaneous acting. It's right in the beginning, after the talk about laundry while being held hostage by terrorists. He says "You, take off your socks, your pants, your underwear, we're doing a wash" and I think this wasn't in the script because Julie Louis-Dreyfus' reaction and especially Jerry Seinfeld's reaction is quite natural. If you ever watched bloopers of Seinfeld (or if you watched "The Clip Show"), you know how Jerry laughs when he laughs for real, naturally. Now, just after Richards says that line, the laugh is the same, if you listen to it carefully, you understand that. Also when the frame is cut to George entering, we can see that both Seinfeld and Dreyfus sit straight, but both were laughing and thier heads were bowed down. I think Jerry Seinfeld couldn't stop laughing after Richards' improvised line and they taped the rest afterwards.