That was the infamous "That's football" game, when the Dolphins stole all the Patriots line calls from a tape, and applied them in a game, and made the Patriots look stupid. When the media found out about it, they asked the NFL's Steve Alic if that was legal. And he replied, "THat's football!" The infamous Spygate memo came out right before the start of the 2006 season, not the 2007 season, as some believed. But after the Phins used the tape to win, and after the Jets were caught videotaping the Patriots, the NFL said it's OK. In the Jets case, the NFL said the Jets received permission to videotape. The Patriots denied it and said no one gave them permission. The NFL said, "But the Jets say they did get it!!"
No wonder Belichick construed the memo to be nothing.