When using Remote Assistance to troubleshoot an issue with a Windows 7 user
running with standard privileges we (the remote helper) are presented with a
black screen (and lose kybrd/mouse) whenever a UAC prompt is shown to the user
(who can see it just fine)
According to Microsoft this is by design
This is how to enable this activity via GPO setting
...and these are the risks of doing so
Hope you found this useful, and I'm curious if you decide to make this change or not.