If you wanted to attend the Colorado Symphony Orchestra’s first-ever marijuana-friendly concert last week, you had to follow the rules.

First, you had to be one of the lucky 250 or so who scored an invitation to the event, since the May 23 brass quintet concert, the first of four “Classically Cannabis” fundraising shows in the symphony’s “High Note Series,” wasn’t open to the public. Then, you had to be at least 21 years of age and bring your own cannabis. Finally, warned a lengthy disclaimer on the Web page for the event, each of the guests who donated at least $75 to attend assumed all risk associated with using pot; concert-goers had to agree to not hold accountable “the Colorado Symphony Orchestra … and their owners, partners, employees, directors, officers, agents, affiliates and related entities” if something went horribly wrong.

This is what happens when you put on a pot-themed classical music concert: you get a lot of rules—not to mention a lot of attention. Reporters from the New York Times and the Times of London prowled the gallery before the show and a camera crew from CBS This Morning zoomed in on the brass quintet as they straightened the special green ties they were wearing for the event. Well-dressed patrons—many of whom were associated with marijuana-related law firms, consulting companies or similar businesses—perused the modern art on the walls, then braved the evening drizzle to grab gourmet tacos and popsicles from the squadron of food trucks stationed out back for the event. In a corner near the front entrance, the dispensaries that, along with a soil company and Leafly, a Yelp-like site for marijuana strains, together shelled out $30,000 in event sponsorships manned schwag tables offering up promotional rolling papers, lighters, and glass storage jars. “We have vape pens as well!” announced Evan Butman, general manager of Wellspring Collective, producing a thin black device from his pocket. Just then, one of the event organizers hurried over. “You cannot give those out to anyone here,” she warned sternly, gesturing at the offending vaporizer.