It comes down to either respecting authority because they're bigger than you
or respecting authority because they deserve respect
If you tell a kid why something is wrong than they will realize that they shouldn't do that thing and generally won't. If you just spank the kid, then s/he'll just try to do it without you knowing next time.
(Nice to see other people linking to Soft Linking to Offend. It shows that I'm not the only person against anonymous--or any other--personal attacks.)