The accused, GM Falko Bindrich, has responded to the accusations that he cheated during last weekend's opening matches in the Bundesliga. Readers can (and, obviously, will) make up their own minds about this; I'll offer just three comments.
First, a player's privacy concerns are a legitimate factor, and if cell phones aren't banned from the premises there has to be some sort of accommodation. (All the more so for club players in ordinary weekend Swisses, whose livelihood doesn't come from chess and must attend to the cares of everyday life.)
Second, contrary to Bindrich's protestations about possible jeopardy to his business and personal life, perhaps all the arbiter needs to do is check the chess apps. (I suppose someone could have texted him moves, if the games were transmitted live over the internet, but one would assume Bindrich would have deleted them immediately.)
Third, while Bindrich downplays the quality of his play against Tregubov, the annotators for the Chess Evolution Weekly Newsletter (either Arkadij Naiditsch, Csaba Balogh and/or Kamil Miton - all quite strong GMs; the former over 2700) look at that game from move 41 on and find White's play extremely impressive.