Fedora 12 Package Policy Changed
The Fedora 12 release contained changes in the default PackageKit behavior that allow installation of packages by users in cases where:
- the user is logged in on the local console, and
- is installing packages signed with a previously trusted key, and
- is using a previously configured and trusted repository
After more discussion and thought, though, the package maintainers have posted to the fedora-devel-list mailing list agreeing to provide an update to Fedora 12's PackageKit. The update will require local console users to enter the root password to install new software packages. Details on the changes are found here
1)
I don't think this is a good idea. Package management is affecting the whole system and that's under root user's concern. Or things will get complicated.

Discussion