Oh boy. Do you guys remember when I tweeted about testing windows earlier today?

Very relevant for this pre-print about false negative rates in SARS-CoV-2 testing!
https://www.medrxiv.org/content/10.1101/2020.04.05.20053355v1.full.pdf

The authors report on serial (repeated) testing over time of the same infected patients. 298 tests on same 30 patients.

False negatives are a function of time since onset of symptoms.
Day 1? ~7% false negative.
Day 10? 40% false negative.
Day 20? 90% false negative

So here you see the impact of testing windows! RT-PCR testing being used now for screening is useless a week after the first symptoms appear. It's no better than a coin flip.

TL;DR:
IF PEOPLE HAVE TO WAIT DAYS FOR TESTING, YOU MAY AS WELL NOT TEST THEM.