The only instance where they've said that it would be open and wasn't (3.1) was a logical follow on from 3.0 not being opened - not ideal but hardly grounds to suggest that when they categorically state that they're opening it up and that someone has been working on doing that for six weeks they're "making shit up".
But in the larger picture, Google has been calling Android open source from the beginning. They haven't released source for 3.0, 3.1, or 4.0. (Yes, the 4.0 devices haven't shipped yet, but if they're really shipping in a month, the code has been in QA for a while.) That's disingenuous, to me.
And if you don't mean to accuse someone of making shit up the easiest thing to do is to not use the phrase "making shit up".
Your stat about the 98% of Android devices is somewhat convincing. 3.0 and 4.0 aren't a fork for tablets though, are they? Future phones will use 3.0 and/or 4.0, right?
3.0 was essentially a fork for tablets. 4.0 is where they merged that fork back so it works on both phones and tablets, which is why they will be releasing the source of 4.0.
This says to me that Google felt that the user experience on phones is so important to them that they're ok with a closed source fork for tablets as a way to keep people from running Android 3.x code on phones and having a poorer user experience.
"Pre-announcing" suggests that the announcement will be followed by code release. In the case of 3.0, I think the first devices shipped back in May-- that's about 5 months ago. With that history, this seems more like "making shit up" to me.