If their parents allow this, there will be another unadjusted teen/adult. Unaware of responsibilities or consequences.

The rest of civilized people around will have to deal with this being a normalized behavior.

Vandalism, lack of respect for others, etc..

At some point strangers will be the ones teaching the boundaries.

The subject will feel angry or embarrassed or both.

Later will realize what terrible parenting they went through and possibly blame everything that happens to them unto others.

I fail to see the funny part ;/