Not sure what you mean regarding tennis as 3 seeded players on the men side withdrew from Wimbledon due to covid positives this week.
I just heard a story there is a silent pack, confirmed or not, for players to not do any self-testing, just for the reason you noted.
Alize Cornet claims players HID their Covid symptoms at French Open
The 32-year-old, who is currently competing at Wimbledon, comments come as a number of top players have been forced to withdraw after receiving positive tests.
www.dailymail.co.uk
PS: Sorry for the Daily Mail link