PAX, I'm glad you posted this. I do not want to
ther_beatingA_Dead: but do want to think this out, and appreciate you bearing with me.
First, the only truly safe thing to do when questioned about ANYTHING by LE is to INVOKE YOUR RIGHTS. "Am I free to go? Am I being detained?" Let's say LE says, no no no, not detained, just want to get your input. So you start answering questions because you trust LE.
At some point as you answer questions, you become a POI in LE's mind. They absolutely DO NOT have to tell you when that happens. They do not have to say "This random questioning is now an 'interrogation'." In fact, they will do everything they can to keep you talking.
So let's say at some point in the "discussion" you ask again, "Can I go now?" If the answer is anything other than a clear and unambiguous "Yes, here's the door, have a good night," then you are being detained.
They don't have to tell you you are being detained even if you ask directly, and they can make detention as comfortable/unobtrusive as they deem necessary to get more information. But if LE doesn't immediately show you the door after asking "am I being detained," then the best response to them is, "I choose to remain silent and I want to see a lawyer," and then STOP TALKING. If you ask for a cup of water after invoking your rights, you ask this way: "I want a cup of water, and I choose to remain silent and I want to see a lawyer."
Given what's been posted about Miranda and fruit of the poisoned tree arguments, this is not going to be a problem in AB's case. AB and her guardians probably did not understand these rights and how they work, and in this case, that's fine by me. But IMO every citizen needs to understand these rules and how they work both for and against investigators.