Billy Strings closes his version with the following stanza:

If your hair's on your ears, there's sin in your heart
Get it cut today, and make a new start
You'll live a life of fear and dread if you listen to the Grateful Dead
If your hair's too long, there's sin in your heart


Apparently in one show, the Grateful Dead line was replaced with "You'll live a life of fear and manic / if you’re listening to Widespread Panic" (Reddit), though the GD version seems to be the main.