Yes SRO in "boxes" is a thing. Now, telling people they have to stand on the concourse is a different thing.
For what it's worth, there exists a plan to build an external concourse for Gampel. I've always guessed that as a part of that they would utilize the internal concourse for additional seating. Putting in boxes at that level makes sense as a part of that plan. And the problem is Connecticut has said they don't have the money to do it. Maybe this is a feeler to gauge interest, as part of a halfway measure where they only build out one or more "corners". If so there would be a new external concourse just in those areas. Just a guess.
View attachment 92051
(Rendering from 2015 master plan. It was scheduled to be completed by 2025.)