Sorry, but this has been rejected by the scratch team for the following reasons:

The Official List of Rejected Suggestions wrote:
8.4 Show when users are banned
For privacy reasons, the Scratch Team does not share such account information with anyone other than the account owner. In particular, a banned user may not want to reveal the fact that they were banned to the public.

However, giving a Scratcher the option to publicly show if they are banned is NOT rejected; you can discuss it on this topic.

Please read The Official List of Rejected Suggestions before suggesting anything.