The "unlock your phone" part is obviously a problem, and the focus of HN's attention. What gets me is an Officer can say to your face "You are not under arrest" but then handcuff you, take you someplace against your will, and detain you there without access to a lawyer. How can that possibly be the conduct of Officers in a free country? I could even understand if the Officer just plainly said "we can not let you boar…
This might be the "internet tough guy" in me, but if I was travelling alone I'd ask the officer if I was under arrest, and if they answer no, I'd ask if I would be under arrest if I walked away. If the officer says yes, I'd get up and walk away (not towards a "secure area"), proceed to get arrested, and immediately ask for my lawyer, and would say no more.
Edit: changed words around to make it more clear.