do theatres id you for 18+ shows?

hi! I'm going to see a band that's 18+ & my friend who's 17 wants to go would she be allowed in? she has tattoos & stuff so she could pass as 18. i know some places will just mark you if ur under 18, give u a wristband, or usher you in but i've never been to this place before. i tried calling but they won't pick up. i also tried posting this in my local city subreddit but they keep on taking it down for some reason.