Once a device is blocked by a the policy , the user is not getting any notifications once he tries to access that device (for example : Device blocked by policy or something relevant)
It seems that this is not the case. The user is not able to view the devices connected under the "my computer" and there is a message from sophos saying that it was disabled
However, there are cosmetic issues on the report by UTm (attached)
The URL is not within the area box and the "deviceControl" should be "Device Control"