What exactly are the risks of an innocent person talking to LE? Just talking to them, from the confines and protection of his own home. As BL could have and should have done immediately, with his lawyer present. I can see no risk to him whatsoever but maybe I'm not imaginative enough. You can talk to cops with your lawyer present. He didn't even do that.
If he was innocent there would be nothing at all for them to "catch" him saying or doing.
If he was partially guilty there would be, but whatever he did he should take responsibility and tell LE and the Petitos what happened instead of running like a coward.
BL's a privileged young man living with his parents in "good" neighborhood. Nothing was going to happen to him from talking to LE, IMO.
I need to be careful to avoid politics so I can't be as explicit as I'd like re: the bold portion above.
People have gone to jail or been penalized in other ways when they committed no crime prior to talking to LE. I am not saying that's a common outcome but it does happen. And it doesn't only happen to people from "bad neighborhoods" (although acknowledging it can happen at all partly answers your initial question, I think. And BL shouldn't be held to a different standard because of where his parents live.)
No one has to talk to LE. We can't be compelled to speak. And talking in one's own home vs a LE office doesn't make a difference re: risks. Finally I'd argue that no one is 100% innocent of everything.
I hope BL is found soon. And IF his parents did anything illegal, I'd expect them to face charges. But not speaking isn't a crime.
JMO