I wouldn't doubt that this could be a disadvantage as well to the opposing teams. If you go in thinking you what "right monkey banana", or whatever nonsense they scream at the line, then the Giants can manipulate you by changing what that means.

So you might expect one thing, only to be surprised when the ball is snapped. In addition, the amount of information they can gather from tapes of previous games would almost be more useful.

However, overall strengths and weaknesses are probably well known by former team members. This is probably known by opposing teams anyways.