The problem is not that you can't smack your kids. The problem is that for some parents that was the only way they knew how to discipline their kids.
Anyone want to tell me that this parent needs to smack his kids for them to know not to cross him? 
My dad through me and my brothers n64 down a 15ft tall staircase when i was 12 because my older bro broke my dads gps (that was when they were knew and ****ing huge too). I started crying shortly afterwards because i paid for half of that thing. The cool thing is that is still worked perfectly despite broken casing as opposed to my dads completely broken gps.
Anyway i will be 23 in october, and first found the fs1 demo and fs2 demo when i was 15, and shortly bought fs2 later that year.
Spanking is universal and works great. It's like what the bible says, don't spare your child the rod(don't spare your child punishment and correction). A thump on the head or whack on the bum creates pain. And pain = lessons learned fast...or very slowly in some cases in those kids who just don't want to learn. While some other punishment techniques that may be considered modern and non-abusive or whatever bs. While some of those may work, giving your kids a beat down is way faster and easier. In my mind as effective punishments with taking your kids' stuff away from them a second place for speed and ease, beating up your kid is the way to go.
I always got this spoon
And it hurt like a *****, though my brother hardly ever got this spoon.
He did get this one
And they did eventually break it on him too
