News
The BWF just released a guidance to clarify the laws regarding "delay of service".
https://corporate.bwfbadminton.com/news-single/2024/12/17/player-update-service-undue-delay
This makes it clear that the receiver should not stand with their hand up to delay service and the server should not use the side to side motion before striking the serve.
"The Laws of Badminton, Clause 9.1.1, state that neither side shall cause undue delay to the delivery of the service once the server and receiver are ready for the service."