User blog comment:Sannse/Blocking Best Practices/@comment-4129195-20121008210714/@comment-8-20121008224509

The goal of the block is the same in both cases - to prevent damage to the wiki. So the block length can be the same, it will prevent them vandalizing more in either case.

And remember, if the admin isn't around and someone is vandalizing, the VSTF are available to help :)