OP can try what my mom did, slowly walk away and act as if you intend to leave him. For me the fear was enough to snap me out of any tantrum.

*out of the house

OP could also explain the consequences directly. Once when I was very young, I got into an argument with my mom and threatened to report her child for abuse because I didn't like the punishment she was giving me. She looked me dead in the eye and told me to go ahead. She explained that CPS would come and take me away and I'd be put into the foster system. She said that if I was lucky, I'd get adopted and be raised by total strangers, otherwise I'd spend my childhood in a group home. She explained that she probably wouldn't ever see me again as she wouldn't have visitation rights. Then she very calmly asked me if that was the life I wanted. I never even thought of pulling a move like that again.

Not everyone has someone they trust to babysit their kid or have the money to spend for a sitter.

I see what you're saying, 7, but learning how to behave in public is important for kids, too. Also, kids should learn that even if something's boring, sometimes you just have to do it—that's part of life. Not to mention how expensive getting a sitter for every shopping trip would be. I used to nanny for a stay-at-home mom, and I know how much they paid me to watch the kid while she ran errands. That's not something a lot of people can afford.

In some cases you can't leave the kid. My brother is not quite right in the head, he's got serious issues. Every time my mother tried to leave us with a babysitter he would slam his head into the walls and even hit the person, my mother usually had just enough time to go to the car before the babysitter begged her to come back. Before anyone mentions it, no, hitting him had no effect nor did punishing or talking. Some parents also don't trust strangers with their kids, which is understandable, some can't afford it, some kids are afraid of strangers and can't be left alone with a person they don't know. you can't just tell a parent to "leave their kid's ass" because guess what ? Usually when a parent is "dragging their kids along" they have a reason to do it.

That's not even remotely how things actually work.

#7 you dont have kids, do you? while understandable, your comment is seriously flawed. if you dont take your kids with you to the store or two a restaurant, they will not be socialized and will not learn.... a store and a restaurant are meant to be family kind of places. there is a reason i have never and will NEVER be angry about a screaming kid in a store or a restaurant or anything. this is life....

some people can't afford babysitter's

No doubt the parent would be arrested for child abandonment or some such, should that plan be enacted. D'jever notice how that sort crap never happened back when it was socially acceptable to spank your kids for misbehaving? Not saying anything, just saying.

Actually it did happen, happened to my older sister when she would act up in the store, she soon stopped when she couldn't find my mum

#18, I highly doubt you would be arrested for child abandonment just because you walked a few feet away so your kid couldn't see you to teach them a lesson. Now if you actually left the store and drove off then I could see that becoming a problem.

I was also thinking something similar, except my version was harsher: telling your kid that the next time he/she does that, you'll leave without him and that you won't come back. It's terrible, I know, but sometimes, you have to use fear to discipline rebellious children.

That's illegal if not frowned upon in most civilized countries.