No, he just said 5% had an invalid header, no claims were made about how many had valid headers. And unless he's actually audited any of the websites to see if what they're claiming in their P3P policies corresponds with how they actually use their cookies then how many sites have well formed headers is beside the point.
It's not really that unbelievable: Microsoft is berating Google for sending invalid P3P headers and this paper describes that Microsoft is sending invalid P3P headers.
Microsoft does not always fully comply with the letter of the law...
In this case what constitutes the letter of the law isn't really clear. As far as I can tell this is the latest specification for the P3P header:
This Internet-Draft will expire on August 6, 2002.
So it's at least arguable that there isn't a standard for the P3P header, and whatever anyone wants to put in it is just whatever they put in it, nothing is invalid and everyone is fine.
Only IE supports it anyway, and it's not like it prevents websites from doing things they've said in their P3P headers that they're not going to do. And the header is required to make IE accept 3rd party cookies (which are needed for lots of quite normal stuff on the web) you need to send it one of these headers.
Because if you don't allow people to bypass the privacy controls a significant chunk of the web stops working. For instance there's at least one well known WiFi hotspot service in the UK for which the block 3rd party cookies option in Firefox breaks the logon process for.
Firefox dropped support for P3P in Firefox 3 because "p3p isn't an effective way to establish trust with a site. it's a one-way system; anyone can say they're the good guy." See item b: https://bugzilla.mozilla.org/show_bug.cgi?id=417800#c11
I've had ICS on my Nexus S for a few months now and I've not seen issues like that. I'm just using the standard Google image (AFAIK, my brother did the upgrade for me - Android 4.0.3, kernel 3.0.8-gb55e9ac). I do see a lot of battery drain when I'm using the GPS, and I don't play games, but no crashes.