International athletes already have lots of opportunities to leave the country for competitions, they just have to stay once they are there. Happened literally dozens of times during the Cold War. As for visas, the US has given EB-1s to lots of athletes from other places. I'm a figure skating fan and due to the scarcity of male partners in dance and pairs, it is very common for US ladies to find partners abroad and bring them over with the EB-1. In years past, Russia didn't even quibble or try to prevent skaters from leaving, as they view individuals as disposable and easily replaced. There are more reasons than war for some athletes to want to leave Russia!