Claimed Revoke, Director called rather late.
I was called to a table (I was playing director and had not played the board concerned). After the play on a board was completed declarer claimed a defender had revoked but one of the opponents did not agree and the other (playing peacemaker) was inclined to accept. The defenders cards had been put back before I was called and the atmosphere at table was frosty to say the least!
Since the cards were not all available, there was not entirely satisfactory agreement as to whether or not a revoke had happened I was inclined to rule no penalty on the basis that I had not been called to table timely.