The user can wipe a device via the web client.
1. Login to the web client, and select "Devices" in the navigation bar to the left.
2. Left click on the device you want to wipe. (Your selection is marked by a darker background.)
3. Click the "x" button in the top-right corner. This will block the device and wipe it.
This means admins cannot login and wipe devices for users.