I was just thinking about what Mangini set in motion and why other coaches would be pissed off and it's really bad when you think about it.
It's common knowledge that just about every team does something "illegal" to gain an edge. It's just part of the game but think about it, if you're a coach, you now have to worry about every piece of intelligence in your arsenal now. If someone with access to this information ever leaves, you're taking a chance that they'll blow the whistle or worse, take information with them and expose it like Mangini did. This puts every NFL coach at risk now.
If I'm a coach, this is a huge issue. Everything I've gathered that might not be 100% above board is now a huge risk. If I keep doing it to gain an edge, I'm risking my career. If I don't, someone else might continue to do it to gain an edge and I'll be putting my team at a disadvantage (and my job).
This is a real nightmare if you're a coach. I think they're furious about this.