LAKE BUENA VISTA, Fla. -- As the NBA prepares for the arrival of team guests into the bubble for the start of the conference semifinals this month, the league is requiring players to provide proof of "long-standing relationships" with non-family members, according to a memo obtained by ESPN.

The NBA and National Basketball Players Association negotiated terms that preclude players from hosting guests who would be deemed as wholly casual in nature, including "known by the player only through social media or an intermediary," according to the memo.

Those without "an established pre-existing, personal and known relationship" won't be allowed into the bubble, where each second-round playoff team has been allocated 17 hotel rooms for guests. The earliest guests could clear the quarantine process and join players is Aug. 31, according to the memo.

As one general manager told ESPN, the issue of casual acquaintances "could create problems within your team -- and maybe someone else's too" and has been a significant topic of discussion among organizations hoping to minimize internal drama as the playoffs unfold.

So far, the NBA has been thrilled with how it has been able to maintain a campus that is free of the coronavirus and largely functional and collegial in nature. On Wednesday, the NBA announced that it had zero positive coronavirus cases from 342 players tested over the past week.

The league and union have been united in wanting to find ways to best preserve the elements that have made the environment workable, and still acknowledging the length of the stay for advancing teams makes the inclusion of family an important factor in the mental and emotional well-being of players.

The NBA and NBPA negotiated the broader inclusion of family and friends after the first round of the playoffs, essentially agreeing to replace the population of exiting team traveling parties with as many as four guests per player, plus additional exceptions for children.

There was significant discussion and planning about how some guests could impact the league's environment, and that's reflected in the language of rules that prohibit those with business relationships, including agents, chefs, trainers and tattoo artists, according to the memo.

Families and guests will be required to quarantine for seven days off-site from the ESPN Wide World of Sports or three days in the team's market before taking a franchise charter flight to Orlando and then four more days on the Disney campus, the memo said.

Players are allowed one ticket per guest per playoff game, with an additional seat available to a child 32 inches or shorter, according to the memo. In trying to control infection in the bubble environment, family members won't be able to move outside the campus zone and go to Disney's theme parks.