Im not a parent yet but I have seen kids in the stores sometimes disrespecting their parents with such audacity and explicitness that I damn near ran them over with a shopping cart myself. One kid, around 9yrs old was ripping open toys and throwing them at the parent and when verbally reprimanded with a reasonable and tactfull voice from the mother, the child screamed "F*** YOU B***!!" so loud the whole store could hear and the parent tried to calm the child quietly to no avail for what seemed like 10min. The parent found no use in even getting the child to leave as he sat down and she wasn't about to drag him while sitting or carry him out kicking and screaming so she walked away to another aisle for a bit to let him cool off which didn't really help either.
Now I understand this might be the fault of the parenting in this situation over time allowing the child to take a dominate role over the mother who is too nice to do anything OR maybe the child knows mothers wont do much while in a store filled with cameras and witnesses these days. I know my brother and I took advantage of it on a smaller scale when we were kids, we would act out and fight or run around like idiots and never take the rebuttal of our mom serious as we would at home, testing her limits in public shops seemed fun and exciting I regret to say it. I could see adding a bad diet full of sugar, caffeine, bad friends at school and violent tendencies to a 9yr old these days could easily lead to what I saw in the store.
However if counseling a child, time out, taking away allowance, further counsel and reason including other authority figures and role models stepping in and yet the child does as the one I first described does without let-up, what do you do? How do you guarantee this never happens even if you have 10 children?