Charter Communications' CEO, Tom Rutledge, is leading an industrywide effort to crack down on password sharing. It's a growing problem that could cost pay-TV companies millions of subscribers -- and billions of dollars in revenue -- when they can least afford it. Bloomberg reports: Cable and satellite carriers in North America have lost 3 million customers this year alone. But the prevalence of password sharing suggests many of those customers, and possibly many more, are watching popular shows like "The Walking Dead" for free, robbing pay-TV providers and programmers of paying subscribers and advertising dollars. Most pay-TV companies only require users to re-enter their passwords for each device once a year. During contract negotiations this fall, Charter urged Viacom Inc., home of Comedy Central and MTV, to help limit illicit password swapping. The cable company wants programmers to restrict the number of concurrent streams on their apps and force legitimate subscribers to log in more often, according to two people familiar with the matter who asked not to be identified discussing private deliberations. ESPN, meanwhile, has reduced the number of simultaneous streams that it allows on its app to five from 10 and is considering cutting that to three, Connolly said. ESPN wants to work more closely with distributors to validate subscribers when there are high volumes of streaming on its app outside the cable company's territory.