What is the rule? You can't have alcohol at the site, or you can't have it during the round?
The PDGA announcement cited sections 3.05C and 3.03B.10 of the Competition manual:
3.05C: Players choosing to use a caddie will be solely responsible for their caddie's conduct from the two minute warning until the player's card is turned in. Misconduct by a caddie may subject both the player and caddie to disqualification and/or suspension.
3.03B.10: Possession of alcohol from the start of play until the player's scorecard is submitted is not allowed. Such possession shall result in immediate disqualification at PDGA events sanctioned at B-Tier or higher. The Tournament Director may, at his sole discretion, elect to issue a warning to the offending player in lieu of disqualification solely at PDGA events sanctioned at C-tier and below. If a player has been previously issued a warning for alcohol possession at the same event, all subsequent violations shall result in immediate disqualification.
I don't think Val got burned really; it sucks for her and the event, but it's in the rules and she should definitely know better. The NT, with all respect to the DGPT, is the premier disc golf tour, and as such, is where professionalism matters most. It is not unreasonable, then, to hold the largest stakeholders for the sport becoming more professional (the pros), to these high standards. That's not to exclude alcohol sponsors from the sport, but to set the expectation for behavior on the course. For example, even though the Colorado Rockies play at Coors Field, you don't see them chugging Coors in the dugouts or on the field. While that at one time was just part of the game, nowadays it's changed, and even if the old ways were better, I really don't see a way to go back to them.