Thank you for reading and responding. So far I have not recieved any unpleasant surprises about having passed it on. As it turns out rapid tests are about 70% accurate when symptoms are present and about 60% accurate otherwise. Good but not great. Here's the link. https://www.healthline.com/health/how-accurate-are-rapid-covid-tests#how-accurate-is-it

Heathline seems reasonably authoritative.

The thing is when I took it I had not yet looked this stuff up or I might not have leaned on it so heavily. Or maybe I would have.

But my overall point as I mentioned in there somewhere is that things are just so messy & complicated that we really can do nought but take our best shot and get on with our lives.