I don’t know how it is at JetBlue, but at Spirit our grid is required to be a minimum of 75% green prior to the first round of trading. Granted, a particular day could only be green by 1, but still, we have a hard floor as to what the grid starts as.

EDIT: Also, to make a particular day green to meet the 75%, it greens up all other days, as they are all equally weighted (except Christmas, Thanksgiving, New Years and the 4th).