Hey, we all know what happens when someone whacks Konokas rear [strike]and isn't Setsuna[/strike]. DOOM. Remember the Kyoto Arc? Caused quite a pissed off Setsuna when the villainess gave Konoka a spank :>
Setsuna is jealous, yo. ^^
I am just pointing at canon XD
Edit: Thus, I got absolutely no problem with Konoka being spanked *as such* It just would not be a very healthy thing to do - unless, of course, you manage to somehow get Setsuna to do it. Then, of course, she cannot get angry at the one doing it.
She would, however, pass out in the middle, due to excessive nosebleed.
Daughter of Edit: As you see, Setsuna is quite fond of said behind

Aftermath:
http://i56.photobucket.com/albums/g1...VA-Large17.jpg
Any question? XD