People who do not care can do anything unrestrained. This would be the bold psychopathic serial killers who do not care about anyone. This would be people who just don't care what other people think of their behavior in general and so they can do exactly whatever they feel like doing at any given moment. These people are actually quite rate but they do exist.

These people are rare precisely because while having no compunction acting unethically they are subject to other kinds consequences of their actions just like everyone else, including retribution by injured parties.
This is, in fact, why the emotions forming the basis of conscience evolved in the first place.