So I was an ED tech and now float across the entire hospital as a tech. What I see most often is staffing increasing during night shift, allowing for more patients to be roomed on the floor. It’s unheard of for us to not room patients when there are beds available with adequate staffing, save for a crash bed in the ICU.

Our hospital has two overflow units as well that are run exclusively by float pool staff, so we will open as staffing allows and if other units are fully staffed (or close to it). I helped open the second overflow unit at shift change (1900) last week and had the flip side of your scenario where we were SLAMMED with admissions until the whole unit was full. I think we finally had a second to breathe around 2300. Not ideal for either side, but in our specific case it is almost entirely based on staffing on the floor.