agree its prettt random, though checkin in online ASAP and gettin to the airport early for bag drop helps.
Flew PVG -DXB in april, we got bumped to J seat but economy meals, which still came with J starters and desert, and J cutlery/tableware. the silvers behind us got nil. Think that flight on the a340 is popular, and they sent us email offers for 1 way upgrade a few days before, which i suppose is a good sign that economy is overbooked!