At our vaccination clinics, we equip each station with a small American flag fastened to a long stick. This flag is waved to signal to the line managers that a vaccine administrator is ready for her/his next client. This was suggested, incidentally, by a retired sergeant major who works for the local Emergency Management Agency, and we have found it to be an effective technique in large, noisy venues.
There we were at our local Big Corporation today, with the ranks of our nurses reinforced by half a dozen EMTs who volunteered from local fire departments. Strapping lads, all of them (we had to make an emergency run for size large surgical gloves).
They were lounging in the back, flicking their flags rather half-heartedly, when a quartet of attractive young ladies from the Big Corporation call center walked in for their shots. By golly, suddenly the back of the room looked like a George M. Cohan musical.