I think the walkthrough tape is a ruse. I think there is some reason we do not know yet that his end game is immunity from prosecution. My guess is that he wants to write a book, and will fill it with lies. He had a clause in contract with the Pats that prevents him from sharing inside info. Therefore, if he writes a book, particualrly one with lies in it, he will be sued by the Pats, and I suppose ultimately would lose the money he made on the book.
So, he creates the walkthrough tape ruse, makes it sound like he has incriminating evidence on the Patriots, in order to get the Specters of the world to force the NFL to do whatever it takes to find out what he knows. Pressure is on to give him immunity. He gets it, there is no walk through tape, or one that is him leaving the camera on as he leaves the field after Pats practice that shows them stretching or something.
Then he writes his book, and has been given full immunity that the Pats can do nothing about him violating his contract.
It actually seems pretty obvious to me. Here are some inconsistencies that support this idea.
1) Does anyone really believe that he would have been allowed to stay and film the Rams walk through and they would not have noticed or cared? This has been totally overlooked in all of this. How could it happen that the Rams wouldn't see him with a camera in his hand taping the practice?
2) He is pushing EXTEMELY hard for immunity, and demanding full immunity from EVERYTHING. You don't require immunity unless you did something wrong (or will do something wrong)
3) This came out SB week. Why? Well, if the Pats won, they made history, as a 19-0 team. Of course, that increases what anyone would pay him for a book about what he knows. Leaking it during SB week, just happens to put it in the news, at the time, and at the venue that the most possible media will focus on it.
4) If the allegations were true, he would have blackmailed the Patriots with them when he was fired. When you have a 'get out of jail free card' you use it at the point you are FIRED FROM YOUR JOB. We are now supposed to believe that Matt Walsh had the evidence that the Patriots cheated in the SB, got fired in 2003, and at that point did not threaten to use it to save his job? Then he decided to wait 5 more years before using it?
5) Again, the timing is probably irrelevant because there is no logical reason he would wait, the timing only coincides with when he had the idea to make up the claim. When the publicity on Spygate was highest, if he had been holding it back all of this time, he would have seen it as his golden opportunity. The reality, it appears, is that it took him 4 months to think up something that he could use to get himself in the limelight.
Prediction: Walsh gets granted unprecedented immunity. In essence, the NFL, bans the Patriots from any action against him for any reason. Walsh's 'evidence' turns out to be bogus. Walsh writes a book, also using the conspiracy theory angle that the NFL knew he was telling the truth and swept it under the carpet. The Patriots are barred by the leagues agreement from doing anything (in fact Goddell may pressure Kraft into signing such an indemnity). Bob Kraft sues the NFL (Al Davis-style) over the Walsh issue, the fines, and the lost draft pick.