Yes, if you start with the premise that everyone is only getting tested every 4 days, you would theoretically have that problem. I have several dozen friends i

Yes, if you start with the premise that everyone is only getting tested every 4 days, you would theoretically have that problem. I have several dozen friends in Hollywood working in broadcast, cable, streaming, and film. They are all being tested at least every other day using the rapid test (results within minutes), with a second rapid test within minutes if the first test is positive for covid. The last time any of them was tested as infrequently as every 3-4 days was back in September before cases started surging again. Right now, almost all of them are being tested daily. Compared to the costs of shutting down production for 2 weeks or more, daily testing is cheap. So, for someone to have caught COVID on set, someone else on set would have had to have (a) been infected, (b) been asymptomatic, (c) received multiple false negatives from the rapid-result test without any positives,(d) and received a negative on their most recent slow test. Can that happen? Sure. Has it happened? No. There are no reported incidents yet of multiple cast or crew members developing covid once they started working on set. While there have been incidents of multiple cast/crew members testing positive for covid, in all situations to date this involved cast or crew traveling to non-local filming locations, with symptoms showing up during the mandatory quarantine period for traveling cast/crew.