Well, this is the thing about civil disobedience. The classic formula is to keep up awareness of your issue by forcing the government to go through the embarrassing and drawn-out process of prosecuting and punishing you. I'll bet they had to drag Thoreau kicking and screaming out of that Concord jail cell when some joker finally came along and paid his poll tax for him. Holding court for his admirers in the town pokey no doubt suited his purposes nicely.
In that spirit, this announcement is very effective. When was the last headline you read about Edward Snowden? If he comes back for a long and drawn out trial that'll show he's pretty hard core about this civil disobedience thing -- if leaving a cushy, high paying job in Hawaii with his pole-dancing girlfriend to go to fricken' Russia wasn't enough.
It occurs to me, though, that this situation is a lot like what I always say about data management systems: the good ones are easier to replace than the bad ones. Likewise the better governments, the ones with at least some commitment to things like due process, are much easier to face down with civil disobedience than ones where being a political threat gets you a bullet in the head, like Ninoy Aquino or Boris Nemtzov. If Snowden *does* come back, and if he ends up "detained" in limbo somewhere, then it'll be time for everyone to go into the streets and bring the government down.