Brick ownership derives from the baseplate the bricks are on.
Does it have to be a baseplate, or can it be any brick?
It does not "use 2148 events". The number displayed during saving includes ownership data, and since you didn't build on a baseplate it has to send the ownership for every single one of those bricks that touch the ground. Good job.
Hmmm, different use of the term baseplate then.
...since you didn't build on a baseplate it has to send the ownership for every single one of those bricks that touch the ground.