I don't think that is how freedom works. From what I observed, freedom modifies the hosts file to redirect communication sent from play app to Google's server. Freedom then acts as a fake Google server, running offline on your phone and sends the false credit card info to the phone's play store app, which thinks this info was sent by Google. When you click purchase, the fake Google server tells play store app that the transaction of money is complete, and the play store app tells the victim app that the payment was complete. This doesn't work on games with servers, because the game also communicates with that server. The game asks it's server if the purchase was complete, and the server asks Google's server the same. Since your fake purchase didn't reach Google, the purchase would not be completed.
In summary, Google doesn't know about the purchases using free-card because the whole thing happens offline.
They can't sue you any more than Ubisoft can have you arrested for playing assassin's creed with a trainer. You have every right to redirect IP traffic going in and out of a device you purchased.
Sent from my GT-I9300