The chances of false positives can be very low as the ministers suggest.
But as millions of school children are offered a test, it can still lead to thousands of people having to isolate themselves for no reason.
If only half of the pupils take the offer of three tests at school, and the false positive percentage is 0.1%, it will result in about 6 000 pupils being asked to be at home next week or so if they not infected.
The rest of their family will also have to separate, which means that if they have siblings, they will also miss school.
What’s more, if the positive comes from the second or third test, the individual’s close contact at school will also be affected.
This means that thousands of children may be wrongly denied the chance to go to school after spending the past two months at home.
But what astonishes experts in particular is that it is so unnecessary.
Having the test confirmed by a PCR test processed by a laboratory will solve the problem.
By holding on, ministers can eventually undermine the whole initiative.