The issue is what the 'expectations' should be. I think everyone is in agreement coaches/chaperones should never be intoxicated. Some of us, however, see a difference between a "drink or two" and "drunk". To me, if the drinks come out after curfew factors into it too, as well as whether the drinking is at the hotel (when they don't have to drive).
But the rules in the OP would have (if followed) prevented BOTH of the incidents you list.
Yes they would have. I am not for/against the team staying together. I stated earlier I traveled from MA to CA at about 13 years old with my team and no parents. I also went on other over night stays and nothing crazy ever happened. They chaperones and coaches had rules and they were followed, although we did try to break a few of them.
I probably wouldn't hestitate to allow my child at the age she is now 10 to travel with those rules with her current team/coach.
But I don't think an association should be able to prevent a parent from saying that they aren't comfortable and want to stay with their child. According to the OP if the parents aren't comfortable then their child can't play in over-night tournaments for any team since its an association rule. Every soccer team must follow those rules.
There has to be a way to get around the rule.