@flo: “Is it supposed to apply to every user no matter what (desktop etc?) they are using?”
If someone needs to do major maintenance on their gmail account, they should go to gmail (mail.google.com) to this. There are way too many other ways to access gmail. The main web app provides the most options.
As an aside, I’m a huge advocate for zero inbox. Treat the inbox as an inbox. Archive any correspondence, and your inbox should only contain items that have yet to be read/processed. Also, Inbox (Google) is a great alternative, even if it’s not quite ready to shed the beta label.