For the staffing part we could have a community organization give each staff member a "grade" depending on how much of the criteria they've met. Then give them an ID number they must display while working.

So just being 18+ would give you a C grade. Background check ups you to B, and training brings you to A. Event organizers must have an A grade, and some percent of staff must have a B or higher.

I'm just trying to think of ways to incorporate this right away. If you start off too draconian then people will ignore you or bend the rules. The grade system is a baseline to build on with better security as time goes on, giving small events time to get up to code.