As I see it the rules are very clear that a DQ was mandatory.
The bigger issue of the whole thing though is the ban on alcohol at that park. Think about how much time and effort goes in to making this event happen, on public land no less, and that it is a giant billboard for the sport. The last thing anyone wants are police or park authorities being called to such an event, even for what is likely a simple citation. Events like that have to be strict, so they can maintain a good relation with the park and local government so the event can happen again. The organizers and TD just cannot gloss over anyone ignoring the law like that. It could potentially spur the relationship with the local park authorities and jeopardize the future of the event and maybe even the course. The risk is just too high to let it go.
Sucks she got DQ for her caddy's actions, but that's the right call all day. Everyone knew the rules, knew the park restrictions, and both were broken. She will live to play another day, and likely be more aware of her and her caddy's actions.