If someone else's child is a rude little ***, do you discipline the child or tell the parent?

Sorry there wasn't room for elaboration in the other space where I was typing. Anyone have stories? My child can really get out of hand so I appreciate when other adults teach him a lesson, it takes a community, and my child needs to learn to respect all adults not just me. But my friend throws a huge fit when anyone even looks at her kid the wrong way or tries to correct her kids behavior, and she prefers the adult tell her and not even talk to her kid. What do y'all think?