Below from Live Scoreboard. Notice all 4 members from China team have Gold ranking in the live scoreboard, but in the final results, China team won 2 Gold and 1 Silver.
I am inclined to believe the China team did not cheat. But they should not have brought mobile phones into the contest area.
Silver - Yaw Chur Zhe, HCI Year 6
Silver - Brian Xiao Boyang, RI Year 2
Bronze - Kang Yiming, RI Year 6
Bronze - Sun Beichen, HCI Year 5