The Law Office of Nadia Lataillade, Esq. | Nadia Lataillade, Esq.
I'm not 100% sure, but my inclination is that your son would be okay. Your son is not a minor. Most jurisdictions, if not all, allow adults to work in bars and serve alcohol. Consumption and vocation are two very different things. Having said that, some individual bars may have him sign some paperwork to ensure he won't consume liquor on their premises. He still wouldn't be able to sit at the bar, but if he's on stage or backstage and not hanging out at the bar, I think it should be fine.
Answer Applies to: California
Lawyer for Indie Media | Sue Basko
Ask the bar owner or manager. There are different types of alcohol licenses and some will allow admittance of those under 21 years. The bar owner is likely the only one who knows for sure what kind of license the bar has and what kind of insurance. It may depend on location, too, because there may be local laws that override the state law. I lived in a college town where anyone 19 and up could legally go to a bar to hear the music, but they were not allowed to drink alcohol. If your son is allowed to play music, be sure he does not drink alcohol, even if someone else buys it.
Answer Applies to: Illinois