Administrators in large organizations may not want to allow all users to be local administrators on their own workstations. There are usually too many users for them to conveniently run the install logged in as a local administrator on each workstation. As a result, they would prefer to 'push' the software out to the workstations from a central server.
Patches cannot be installed silently. This is a limitation of the build of the patch. For instructions on installing patches, refer to How to install a patch.
Another option is to have Blackbaud host your software and manage the installation of software updates and patches for you. For more information, contact your account manager.