You can remove app access from Google options and If I remember correctly you can also disconnect Facebook apps...
Therefore is by the rules as they no longer receive data from your profiles. Saves remain in their database and are their property anyways.
It's also good safeguard to lower account theft/sales ratios. Or stop you from giving away your account as you are trying to do... Have you thought that player with just one account will have to deal versus two or more because of such occurrences...
Also if the person is your friend and you really wanted it that bad for him to have your account... Well you just give him the credentials
