flag strategy
n.— «Another method, called the “flag strategy,” allowed employees to get their inoculation at the time of their choosing—but only when the line had fewer than a set number of people. With a queue maximum of five, this method resulted in a wait of more than four and a half minutes; with a queue maximum of three, it resulted in a wait of nearly three minutes. One major disadvantage was the many return trips necessitated when the line maximum was met.» —“Computer Model Maps Efficient Inoculation Of Hospital Staff In Pandemic Outbreak” in Weill Cornell Medical College Science Daily May 21, 2007. (source: Double-Tongued Dictionary)