A number of deals seemed to be completed at breakneck speed. Kemba Walker committed to the Boston Celtics and Kyrie Irving to the Nets almost immediately when free agency began, and the likelihood of the moves was essentially known for days.

Also close to the time free agency started, Kevin Durant posted a video on Instagram announcing his decision to leave the Golden State Warriors and become a Net. The video appeared on the account of “The Boardroom,” Durant’s sports business channel.

Several news media reports indicated that his teaming up with Irving had long been in the works.

The New York Times reported last month that representatives for Leonard, now the centerpiece of the Clippers, had made it known that he was interested in teaming up with Jimmy Butler, who was becoming a free agent. In addition, according to an ESPN report, Leonard tried to recruit Durant days before he officially committed to the Nets.

(Nets General Manager Sean Marks said at N.B.A. Summer League that Durant had committed on Instagram before ever meeting with the team.)

On ESPN’s website, testimonials from two players — the Milwaukee Bucks’ Khris Middleton and the Philadelphia 76ers’ Tobias Harris — were posted within minutes of each other at around 7 p.m. on June 30, an hour after free agency technically began, to explain why they were staying with their teams.

Agents for several other players, including Jonas Valanciunas, Terrence Ross and Gerald Green, confirmed to The Times, ESPN, The Athletic and other outlets that their players had committed to teams within minutes of free agency opening. Bobby Portis told The Athletic that the Knicks had reached out to set up a meeting a full five days before free agency began.

“The one strong conviction I have is that we should not have rules that are not strictly enforced,” Silver said in Las Vegas. “We know that’s the case right now. Whether that’s by virtue of practice, whether it’s because just the world around us has changed, whether it’s because players have power that they didn’t used to have, I’m not so sure.”

There is some precedent for under-the-table deals that break league rules. It was discovered that Joe Smith, a No. 1 draft pick who played in the N.B.A. from 1995 to 2011, had signed short-term deals with the Minnesota Timberwolves that were less than his market value, with a secret promise that he would eventually get a more lucrative contract. The N.B.A. handed down what at the time was the harshest penalty ever from an American sports league: a $3.5 million fine and the stripping of five Minnesota first-round picks.