For notifying the user regarding the blocked USB a notfication can be created
If you still want to remove the icon, perform the following in SEPM:
1. Go to Clients and choose the group where you want to remove the icon.
2. Click the Policies tab on the right and expand Location-specific Settings for the corresponding location.
3. Click Server Control.
4. If Server Control is selected, click Customize.
5. Remove the check next to 'Display the notification area icon'.
6. Click OK and update.
7. If you have Mixed Control selected, click Customize.
8. On the Client/Server Control Settings tab, scroll down till you see the section for 'Show/Hide noticiation area icon' and choose the Server setting.
9. On the Client User Interface Settings tab, remove the check next to 'Display the notification area icon'.
10. Click OK and update.