Commonly Work Zone users are managed through the IAS and IPS tools that makes very easy to create and delete users.
Once the user is deleted in the IAS, the IPS updates the user list in Work Zone. What occurs next is that the user remains visible in the searching bar.
For example, in the screenshot below I have created 4 users onlý for test purpose, but after that I needs to delete and hide from Work Zone final users.
Following the example, I deleted in IAS but users still appears in the searching bar like shown below.
This users above (mail mail, Usuario Prueba, Usuario Pedro Ximenez) are right now in a "alumni" status and even if they are not active anymore, they are still visible in the searching bar.
Possible solution
It's possible to label deleted users with "alumni" and to block access to those profiles.
To relabel to alumni in the searching bar follow the procedure below:
Go to: Admin Console > Feature Enablement > Features > flag :Clear profile info for alumni
After this procedure the deleted users will be replace with the "alumni" label, as shown below.
To block access to the alumni's profiles, into the same Feature section select the "Clear profile info for alumni" option check box.
Hope this blog helps!