Wikimedia Bugzilla is closed!

The ability to set an expiry time for protection would negate many of the
protect-and-run problems wikis tend to experience. This is particularly true for
time-sensitive situations, such as the semi-protection of a talk page belonging
to a temporarily blocked IP. The protection should be lifted as soon as the
block is lifted, but this is often not the case as it's difficult to keep track
of such protections. 

This is resolved by adding the option to protect a page for, say, 24 hours to
coincide with an IP's unblocking.