The April Fool's spirit lives strong in Caroline Wozniacki - the World No.5 jokingly announced her retirement on Twitter on Wednesday, though most of her fans didn't fall for it at all.
WTA Staff

A few fell for it, for a little while at least, though one had just finished a hectic shift at work:

Wozniacki checked in a little bit later in the day to make sure the joke hadn't grown too many legs:

Some of the other WTA stars had different approaches than Wozniacki to April Fool's Day: