The way you framed this as a “PR liability” suggests you don’t think there’s anything wrong here, it’s just a question of dollars and cents to the company’s bottom line. That’s exactly the kind of sociopathy that is the problem.
You have to stop and decide that there is a moral and values problem, and that these things matter more than a few bucks. If the company has values around this, it will make sure people have training around what is not acceptable behaviour. It will not pass out cards, 10x engineers get a green card, 5x engineers get a yellow card, 1x engineers get a red card.
Everyone will get the same message about what the company values, and steps--I will not say what those steps are, maybe training should have happened before this incident, maybe coaching should happen afterwards, maybe firing is not necessary--and steps will be taken to ensure that everyone in the company acts in accordance with the company’s values.