What would/do you do? (Explained in post)

Reading an argument on twitter that started between 2 parents.

Parent A tweeted about her kid jumping on the couch and how annoying it is, Parent B said she should let the kid "smack their head on the coffee table and let them learn to listen".

I found that comment a bit extreme, and a little dangerous so I wanted to reword it before I put it up for debate

So my question is this:

Would you let your kid get hurt (nothing dangerous, think a tumble or scraped knee) to learn natural consequences, or would you just always prevent situations from getting that far?