MTR 5.2

“Players may not reach an agreement in conjunction with other matches. Players can make use of information regarding match or game scores of other tables. However, players are not allowed to leave their seats during their match or go to great lengths to obtain this information.”

Seeing as the tables in question were right next to each other, minimal effort would be required to utilize any information that would be useful, and they are actually playing games (just making use of MTR 2.4 before someone wins). Personally I see no infraction here. Maybe a bit of a dick move, but that'd be about it.