Never meet your idols.
I seriously stopped being a fan of any public figure because people seeking public attention are mostly off-putting at least. Then come the narcissists and psychopaths, it gets only worse.
This didn't happen at a concert. Yes it is not wise to allow your children to go to private parties unattended with people you don't know though. Especially when if their reputations are tied to partaking in drugs, alcohol, theft, gangs, assault, battery, rape, or murder.
Or don't idolize idiots. Popstars and corporations washed the market so much that they are now accepted by the public as smart or cool. Not so many years ago everyone considered them trashy.
If your idol turns out to be a jerk in real life, is that their fault, or does it mean you’re just a bad judge of character? And I mean generally - not you in particular.
Personally, I’d be more than happy to meet my idols. I’ve listened to them speak for hundreds, and in some cases thousands, of hours on podcasts. Nobody can hide their true personality for that long. I’m confident I already have a pretty good idea of what they’re like in real life. That’s also why it’s so funny when non-listeners try to convince me that they know these people better than I do.