Probably more of an inconvenience to govt snoopers than criminals
Although I think from a sysadmins PoV there's no real difference. They're all information thieves in the end. Their motivation is irrelevant ("We were trained to do it, encouraged to do it and in the end we got to like it," as a former govt contractor might have put it).
It'll be interesting if, when this is implemented someone's server code is broken because they have been using the return fields (I'm looking at you MS) and some developer has been "clever."