in the uk a backhander is a full swing slap using the back of the hand, a more painfull version of a slap, as to the question you are asking i can understand in the cases of restraunts especially after a certain time of day no children allowed, but not in a grocery store or super market especially considering the cases of single parent families who dont have any child care and have no option but to take their child with them, they also need to buy groceries and essentialls,
jw here in uk it is also illegal to smack your child but i agree with that under child protection laws, ( yes as ive said we will smack ethan when needed) but i would be a lot of work and regulation for the government to inforce laws to prohibit excessive smacking, so much easier to just make it completely illegal !