I do think that is true. I've worked in a clinic through the whole pandemic, which meant mandatory tests everyday. Cought two asymptomatic infections this way. With the first one I had a very light headache - I would have thought absolutely nothing of it if it weren't for the test. Second time I've got no symptoms whatsoever. I then got it again for round three and that one suuucked.

Who knows how many had it were none the wiser.