=NCC 1701;459397]thanks jk, but I got that part OK...lol I'm wondering "if" LE can detain you to interview you?
not just because they want to. Unless you are detained, you can walk away. They must have legal justification to detain you.

and if you continue to say: "nothing", can they arrest you for obstruction?
can they arrest you? Sure. Is it a valid arrest? no. Unless you actively frustrate their investigation, you are not obstructing.

Lying is obstructing. Silence isn't.