I was there in 2008 - I had owned Freddie since 2006. I followed all of the news releases and quotes. It was clear from the start the warrants would be exercised. I also had AIG and their warrants were exercised. Every single other company that was taken over - and there were many - the warrants were exercised unless they were so bad off that the companies didn't pay back the government and were liquidated. In those cases the warrants were worthless so were not exercised.
The only scenario when they would not be exercised is if F&F didn't pay back the senior preferred in full - in that case F&F would have been liquidated and the stock and thus the warrants would have been worthless.
Luckily - the warrants motivate the Feds to try and raise the common stock price as high as possible - so the warrants being exercised assures us shareholders will get maximum value.
Everyone has always known this - and that is why nobody has ever sued Treasury over the warrants. And nobody ever will.