Proverbs also says to take a knife to your throat if you are given to gluttony. Is that something that you think is literal? I have seen more than a fair share of gluttony in the modern church.
Also, if it IS literal (and with a name like "proverbs"...I think that is a moot point)...then it must be applied LITERALLY. As in, you beat your child with a ROD on the BACK...not on the bottom or the leg and not with a hand, a paddle, a switch, a glue stick.
Even those who claim it is to be taken literally do not actually take it literally.
And, if they are saying that we are supposed to take the spirit of it...which is to discipline our children, to be an authority over them...well, that is completely in agreement with GBD. AND, it does not require hitting them.