From Yuku Help

Banned

This page allows you to view all your banned members in one go. The features on this page are mostly the same as the all page. You can also view all the same members by using the status filter on the all page.

You can ban your members by using the Edit a single member page or Edit bulk members page.

When you ban a member you are given the choice of how long they are to be banned. You can choose from 1 day to forever.

A note will be added to their edit page with the date. You can also choose to send them a pm about their banning.