I have experienced being in physical restraints and also being in isolation rooms. At the time that's what I needed and was never traumatized by it.

I have also had times where nurses sat outside my room on guard with the door open.

One time the hospital I was at didn't have an isolation room and I was out of control. They kept one of the hallways locked and I asked them to put me there until I could get myself calmed down and they complied.

The last time I was IP they had cameras in all of the rooms. I didn't care about that either.

I don't know about ER departments but I do feel that on psych wards there is a place for restraints, chemical restraints, and isolation rooms in addition to a voluntary unlocked quiet room.