I have witnessed a handful of intoxicated hikers in Pennsylvania, mainly close to main trail/road intersections. It is very sad and concerning that people that are so inebriated want to hike over some treacherous terrain (Pennsylvania rocks).
I tend to avoid all the camping druggies and alcohol users by camping away from trails and trail shelters.
One thing you never do is bring attention to yourself or tell them it is wrong or illegal. Why gain unwanted attention by people who may want to fight when intoxicated or under the influence of drugs.
Hope this helps.