Wow, thats interesting Mori. I received my bachelors in CJ last December (cant believe its been a year!) and here in Tennessee, the TCA code defines robbery as the same as what you state, "the unlawful taking of the property of another by force or fear," however, knowing someone's intent when they enter your house can be skeptical at times... I am always under the impression that IF someone were to break in, that they intended on stealing but such is not always the case. Burglary as defined by the TCA code here is when someone breaks in and steals something. If they are armed, and dont confront anyone while in the commission of their crime, i am not sure how that is defined. But you are right, robbery can be committed without being armed.
We studied a case in CA i believe, if memory serves me correctly, of a man who confronted 2 kids and told them he was going to beat them up if they didnt give him their pizza. They gave in and ran away. He was unarmed, and as he sat there eating, he was soon arrested for robbery.
Edit* It just dawned on me that I pretty much said the same thing you did... I think we just misunderstood one another at first. Oh well.