Handcuffs *do not* equal arrest.
If the officer feels it is necessary for safety purposes, it is allowed prior to an arrest. Of course, at that point, the arrest part is not certain.
I’d suppose though, that in court an officer would have to be able to provide good rationale for the “safety purposes” to be valid.
I’m not sure that’s correct. I believe that you are technically under arrest if they do not permit you to leave.