Make it clear when members are not allowed to go to events

One-sentence description

Make it clearer for members when they cannot go to events.

Motivation

Sometimes members miss the email that tells them they are banned from events (because they forgot to pay their fines). This causes confusion when they cannot register for events.

Desired functionality

Better information on the website when registrations are not allowed.

Suggested implementation

A banner at the top of the site that clearly states when people are banned from something, and to contact the treasurer for more information.