Let's be real here for a second.
This isn't about hardcore raid progression groups. Those people can use all the widgets and gizmos they want. That's a social inclusion thing based on a club you try to become a part of. If they want things of you, fine.
This is about PUGs in the Duty Finder. The vast majority of content is not such that parsers make any sense as anything more than a high score at the end of the instance- a sort of "Hey, I did better that round!" thing.
The way it is now, if you bully people out of DF groups using parsers, you will get your ban and deserve it. If it's something at the end, they can still enforce this. But if it's a constant meter running during the instance, they have much shakier grounds to stop people from doing exactly that.
So yeah, if they implement it, they have to be careful.