Welcome in the 21st century, miss Navratilova. These athletes care for one thing only: winning that final. They will do exactly THAT what they need to do to reach that point. The crowd doesn’t see most of it, but now they enter the court with headphones. Big deal. This has absolutely nothing to do with a lack of respect: they are just preparing for an elite performance and they know/think they need this music to improve their performance in some aspect (concentration, anxiety control, motivation, whatever). Besides that: Wimbledon is starting to collapse under its traditions by now. Only one thing matters: optimal performance of the athletes, that’s what the crowd and TV watchers expect and pay good money for. I would absolutely stimulate it as a coach!