Assign the owner block immediately when placing the frame.
First of all: sorry if I didn't find a similar topic and the translator.
In the safezone filter, the grid filter must be an empty black list to allow the owner to place a block without it being ejected. This allows an enemy to enter safely using a ship assigned to anyone, and use a cutting saw inside the safe that does not respect the limitations.
Configured in another way, it forces the player to use the rotor as a base for new grids. Which is not interesting for dedicated servers.
So, if the board contains built by and owner, it already eliminates many problems (including others that I still don't know about).