Time-outs work. The parent needs to make sure the child sits where they're supposed to, and then talk to the child after time is up. Walk them to the time-out place, explain they are to sit quietly for 5 minutes and think about what they did. After, ask the child why they were put in time-out, and how to prevent it again. You don't need to 'beat' a child! The only time a physical punishment is warranted would be if they're putting themself in danger.
Sure. Everyone got put in the corner to think about what they did wrong. And depending on the child, yes, it can be effective. So can a smack on the bottom but the political correctness police frown on that today.