Originally Posted by
rockridge98
Has anyone else experienced this or know what the back story is?
There is no backstory. Prior to departure, the flight crew must perform weight and balance calculations on the aircraft to ensure that it can be safely operated on the available runways and in flight through a specified flight plan (taking into account weather activity). If there's an issue, then some weight must be either removed or redistributed to allow safe operation.
Standby customers know that at any time, for any reason, they may be asked to deplane and rebook.