That fills in some detail on how the cheating was done. Like the Olympiad case with one of the French team, an engine wasn't strictly necessary. According to the round 1 opponent, it was an accomplice or accomplices who were signalling suggested moves in some manner. That would imply that they had phones or computers with them and were allowed and able to use them within easy reach of the players. For the game against the GM, the players were in another room and the accomplices weren't able to follow the game once the arbiters switched off the display feed.
Use of equipment by spectators and back up teams is something organisers and arbiters may need to think about. A hard line approach would be to insist that devices are off in any area where the players would have access. That may cause problems for parents of younger children.
It's unsettling though when after the game, a spectator, evidently following the game on an engine, points out a winning idea that both players had missed.