I agree it's good to have info; I hired the PI so I wouldn't have to get into a lying discussion about it. If my AH had been here instead of halfway around the world, I probably would have gone out and shot the footage myself.
What I think is important - and took me a while to learn - is I can have all the info and proof I want, but if I didn't take the next step I was stuck. I believe it's possible to get focused on gaining proof in order to get the A to admit something or the other. I realized (prior to the PI hire) that wasn't going to work anymore. It was going to stop - at least from my side of the game.
When I was in denial I could have "proof" of something and then move onto something else I needed "proof" for. It was a nightmare. If I can spare someone just one extra proof by sharing my experience . . .