I don't know why you think there aren't any legal restrictions - this wasn't a random LEO going cowboy and trying to hack into google, a judge directly ordered this action and signed onto the warrants.
I mean as far as privacy is concerned. They were able to request all text messages, documents, location data, voicemails without any stipulation that they were relevant to the case.
Well, yeah. They have to go through them to determine if they're relevant. Same reason a physical search warrant will let the cops seize a vaguely defined bunch of stuff from your house.
