You'd be surprised. My brother used to work for Prodrive and they were constantly redesigning bits all through the season, and the car that started rarely resembled the final one of the season (mainly aerodynamically).
Any of you that have been past or into McLaren's site in Woking would know how much money and secrecy is in the sport. Their site is so large and well protected, you cannot see the buildings from outside the boundary. It is hyper high tech and contains simulations of all the stresses etc. of a racing circuit. Wind tunnels and local tests can give feedback if something is working as a change. In theory, McLaren could have benefitted hugely......
However, I think Ron Dennis is a victim of a stroppy driver and a devious pair of staff from both his organisation and Ferrari's. I used to work for one of McLaren's official professional advising companies, the work being done out of the office I was in. The clearance he expected to put people through before they went in makes UK Government clearance look like a walk in the park. Even when in, getting information was so hard, and they were obliged to give it to us!
I think the reason he put the evidence forward is because he believed he had nothing to hide. Whether that is delusion or true, we will never really know. These designers move teams and there's every chance there could be similar technology between the cars, that is their own IP. THerefore they have the IPR and because of people ignoring the spirit and rules someone who has worked so hard finds himself with a $100m cheque to write.
BTW, I don't necessarily blame Ferrari for calling it. Any of us would do the same, and it's the FIA at blame if they have unbalanced representation on the board.
I hope the individuals get what they deserve.....