If you tell someone they can't leave a room, have you committed a felony for false imprisonment?

Say that you go to a seminar, and they want to teach you about the effects of racism. Therefore, they divide people based on their eye color (to make an analogy to skin color). They then tell all the blue-eyed people to go into a room and stay there. They post a man at the door of the room and he tells the blue-eyed people that they can't leave. Is this a felony for false imprisonment?If you tell someone they can't leave a room, have you committed a felony for false imprisonment?
It becomes false imprisonment when he actually prevents you from leaving. Just by telling you that you cannot leave is not enough. I bet that if you told him that you were feeling nauseous and were about to throw up all over his shoes he'd move in a heartbeat! If he didn't, then I would tend to agree that that's false imprisonment. And in America, that's a felony. Not sure about the UK.If you tell someone they can't leave a room, have you committed a felony for false imprisonment?
It is a felony if they forced you into the seminar with cattle prods... otherwise you went there for the experience of your own free will.
Only if he forcefully holds you there.