A discovery albeit late of this interesting case that happened in the Olympics 2016 in Rio.
The controversy happened when the Taiwanese badminton association or CTBA was sponsored by Yonex, a Japanese sports company.
However, the player in the shoegate scandal is Tai Zu-Ying, who is sponsored personally head to toe by Victor sports.
She is featured prominently in the Victor website, being a local Taiwanese star who is sponsored by the Taiwanese company Victor.
Victor website lists her equipment: her racquet, shoes, bag and shirts.
However, the CTBA or Chinese Taipei Badminton Association is sponsored by Yonex specifically for the Olympics, meaning Taiwanese shuttlers are to be kitted by Yonex shirts and shoes.
She wore the Yonex shirt and pants during a match in the Olympics, with the prominent YY Yonex logos seen here.
However miss Tai Zu-Ying wore the Victor shoes instead of the Yonex shoes. However, she scratched off the Victor Logo so that it was not seen as shown below.
Miss Tai Zu-Ying claimed that Yonex sent her shoes that were not fitting and causing her feet blisters; she has left and right foot that are of different sizes.
Therefore she revert to her Victor shoes.
Under the legal contract between CTBA and Yonex, Tai Zu-Ying committed Ultra vires, a legal term meaning that she acted without the authority of CTBA.
Hence, she broke the legal contract under CTBA. She could be ban for 1 year by CTBA.
Ref: the source, here