legalization didn't change anything here. Gave cops something better to do, it never increased car accident stats. I know more people who are bothered by indoor cigarette smoking than pot smoking. I think it has more to do with doing what you are used to.. one beer will throw me off because I seldom drink. I know others who play fine after 6 , if they drink every day they are just in their normal state.. . will a joint throw off a seldom or non pot smoker, sure it will. An every day smoker, likely no notable change. Probably whats right for you is what you do now, whatever that is. I think if you are comfortable in your surroundings, or not... that makes more difference.. pot smoker don't stagger when they walk because it really doesnt; affect motor skills so much.. drunks stagger and slur their speech, some become obnoxious.. some are happy and just fine.. I've never seen anyone become stoned ( on weed) and obnoxious, maybe a bit silly.. perhaps forget their turn..maybe also set aside the mental stuff that was stressing them internally.. If it helps people sleep that can have positive health effects alone.
Amongst friends, its only the nose powder I'd worry about, so many addictive things out there nowadays that can get mixed in. I've seen that stuff ( or the resulting slippery slope ) turn peoples lives into garbage enough times that those quick trips to nose powder in the bathroom can be a bit worrying.
I've never met a person yet who destroyed their life or crashed their car by smoking weed. drinking , yes many.
I have a few friends who will drive after drinking and I dont know quite how to approach it, thought of maybe putting up a box with $50 cash and cab numbers, ( honor system? ) maybe that could encourage them not to drive home when too intoxicated. Sometimes I find myself wondering if I should interfere but I dont portray myself as the Barney Fife type either..
Maybe a breath checker could be part of a poolroom so you can check for yourself if you had too much to drink before driving.. I'm thinking that and cab numbers and possibly a clear ( breakable? ) container with some small amount of cash is a positive way, rather than ragging on people.. At least that paints a situation where there is an option if a person is too drunk , stoned etc.. I think many may just honor why the 50 bucks is there and respect it but it depends where it is.. Could be a sign that says ask the bar to call a cab if you think you are impaired..
Eating pot can make people unsafe to drive, as it can basically give you too much THC at once, whereas a smoker stops ( says enough - stops) or it stops affecting them when their receptors limit out.. but when it is injested there is no stopping because you feel you had enough,, it simply takes it's course.
I've seen lots of situations where people start cooking with it and then people are basically falling asleep having ate too large of a dose for them.. yes one brownie can take you down, so if you eat pot, be careful, its often so inconsistent.
If people smoke it and don't usually, then it affects them more because their tHC receptors are open.. thats why 1 beer affects me, no tolerance..
Then I think you can be impaired by it.
I think the only way a drink or a toke helps is if the person is used to it and then they are just basically their normal self.. Either is going to affect the intollerant and will throw them off..
maybe some need to question why they play, if its to have fun, That's different from serious competition..
If you enjoy to have a toke or a beer and play then who's to say that's wrong for you.. You decide that..
Oh that was Good stuff. 
