During 3x3 Blindfolded Round 2, a competitor was using the nod-don technique. Immediately after the solve, he informed the WCA Delegates that he thought it might be a bit close to starting the first turn before the blindfold was fully donned. The WCA Delegates granted a provisional extra before asking the WRC for feedback. This might violate Regulations B4a) and B4b):
B4a) The competitor dons the blindfold to start the blindfolded phase.
B4b) The competitor must not apply moves to the puzzle before they have fully donned the blindfold. Penalty: disqualification of the attempt (DNF).
Since the video evidence was not enough to know if the don is legit or not, the WRC agreed to accept the provisional extra as the valid result.