Writing tickets and issuing fines for such things is part of park ranger duties. Improving enforcement and visibility of enforcement nationwide might be able to

Writing tickets and issuing fines for such things is part of park ranger duties. Improving enforcement and visibility of enforcement nationwide might be able to shift the culture. Something you can do: call these people out. Calmly and deliberately explain that people around them are watching and judging them negatively, take pictures of them. Social enforcement of this kind is the most scalable.