This was where high-profile events tended to take place, to show off the bright new shiny things. But you couldn't hear yourself think there. The solution? They turned off the fans a short time before important visitors arrived.
I learned of this when I was chatting with a worker who deals with such things. Apparently, the people who were installing these vents knew that they would be a problem. But who were they going to complain to? The architects don't work here, and the local managers don't listen to their underlings.
There are lots of stories like this in many work environments. I think the common thread is that high mucky-mucks are not interested in talking with the people who are doing the labour.