Operatinal reasons could include delays, cancellations, weather, over booking and the like. Many reasons why an airline might want you out of the way and gone. Of course when there is no reason they are not going to undersell their Flex fares and FF benefits.

Remember that business is only two rows of 4 (n=8) and almost always the cabin goes out full (not unsurprising given the discounetd J fares, points upgrades and agressive bid now upgrades).

KF