Unauthorized Teleport Into Private Setup

Even though I have teleport permissions for other players turned off, random strangers who are not on my friends list keep suddenly teleporting directly onto the exact same spot where I am standing on custom objects placed in areas that are normally unreachable.
I am trying to carefully test and adjust my own Quick Drop setup and these annoying random players keep showing up out of nowhere and getting in the way. It completely ruins what is supposed to be private time and space. This has already happened three times in just a few days.
Whenever these people appear I have no choice but to stop working and delete my objects because the whole setup becomes unusable.
This is unbelievably disruptive. Fix this bug immediately.