I see no evidence of seat blocking...recently flew DXB-SIN on EK354 in Y....A380. Economy was only half full. I pre-selected aisle seat on an empty row. On boarding I found that the other two seats had been allocated . Almost all the other rows in this part of the cabin were single or double occupied. Plenty or room on the flight. This has happened on the last three occasions that I have travelled on this flight...so no block booking by Emirates for FF's.