They would probably force them to 'black out' the shoes. When I worked on the New Balance account, a number of our athletes used to wear nikes blacked out with a sharpie because they were unhappy for various reasons I won't go into here. Nike currently has the dominant long distance running shoe (VaporFly and AlphaFly) that allow sub 2 hour marathon performances, their spikes also have a similar performance benefit and athletes have have deals with rivals like Mizuno etc often run on blacked out Nikes to remain competitive. I could see that happening with China's own athletes at the very least.