We treat children and adults with pneumonia (among other things) in the ER, and they can infect others. Some illnesses simply make folks sick enough for the ER.

I'd not mind a way to put folks further down the list if they choose to be unvaccinated or have folks have a special waiting room - but the ER is no time to figure out if someone chose to be unvaccinated or not. It would take up even more time and resources from an already strained system.