I will coincide using my pass to receive the CDB - well usually but on 2 consecutive days it means little lol.
Base your decisions around activity on whether the player participates in CC events, not the XP contributions. XP's really mean little as WGT missed the mark on this, but any player who plays on WGT should IMHO, spend at least some time playing in CC events or with fellow members.
As for being fair, as the owner you need to set the parameters, and let your members know what these are