This talk is beyond silly. Taking an opponent out at the knees is the cry of the media, the fan, Al Davis, and Bill Polian. Professional football players in 2007 (with the exception of borderline insane people like Haynesworth) do not think like that.
In the free agency era, many of these guys are former teammates and friends. They share the same agents. They go out to dinner with each other. They golf with each other. They make commericals with each other. They make appearances for each other's charities. They train together offseason and show up at each other's football camps.
The players are in the same union. Although it hasn't worked so well in the NHL, the workers don't intentionally try to hurt their fellow worker. Not because of some perceived slight or embarrassment. Even Haynesworth was responding to what he felt was a cheap shot against him.
Honestly, does anybody remember one player intentionally trying to injure another player for running up the score or some other embarrassing situation?
How about we leave this talk to guys like Simmons, Easterbrook, and fans with IQs lower that their pants size?