Assuming the ratio of cases with symptoms to cases without symptoms usually remains the same, I must admit I don't immediately understand why it would be important to determine the amount of asymptomatic cases to determine the risk. It seems to me the growth rate of (symptomatic) cases would be the major indicator for that. (Obviously it would be of general interest, but I mean specifically with respect to gauging the risk).

It all seems to hinge on the assumption that with the implemented "strategy A", nobody with pneumonia would be tested for Covid19 unless they have a known connection to a symptomatic case. That of course would be a mistake. But were people really that complacent that it would never occur to them to test for Covid19, even as the rest of the world is talking about nothing else? (Availability of tests is of course a factor here, but should only be a temporary impediment).

I am interested in it, because here in Germany there also is currently a discussion of the virus spreading silently, only to come back in full force in fall if we become complacent. I must admit I don't fully understand the logic behind that, as surely when it spreads silently, it also has a proportion of symptomatic cases in its wake, so that in the end, it doesn't spread silently after all.