People get fired every day for pasting code that is 80% right and worked on a couple test-cases.
Though SO has a lot of moderation, so it's somewhat self regulated.
Never seen this happening. In contrary still not every team is doing code review and plenty of people regularly fix bugs in production.
One ex colleague invalidated all apple device certificates, didn't get fired.
A previous tech lead wrote code which deleted customer data and we found that a half year later, no one was fired.
And no one got fired at a code review.