Wimbledon umpire John Blom issues a warning for spectators to not pop open champagne bottles prior to players serving. ✔️ Subscribe to ESPN+ http://espnplus.com/youtube ✔️ Get the ESPN App: http://www.espn.com/espn/apps/espn ✔️ Subscribe to ESPN on YouTube: http://es.pn/SUBSCRIBEtoYOUTUBE ✔️ Subscribe to…