I work ACL Fest every year and usually on the barricades, mixing pit, or back gate security. I also get to talk to the various riggers who travel around the country doing these shows.
We have to enforce artists requests if possible (no pics, recording, etc), but for the most parts they're usually all pretty regular people. but you get to hear things too, and observe behavior.
Gary Clark Jr parents=ultra cool and understanding, GC too
Billy Idol=cool
Lars= per a rigger and my observation after he made an after concert speech "Lars is a fcking princess!"
Dwight Yoakam manager=ultra cool and understanding we couldn't let him in after lockdown until Security Director and Stage Manager showed up to verify identity
Eminem=another paranoid princess