The solution I mentioned are fixed rods (screwed) motor end to end so to remove the arms would require one remove these rods.
I'll see if I can find find the post that shows a picture. It was a European vendor.
Wow they seem to be really expensive.
I have also seen carbon arms that go from arm to arm at the end of the arms. The problem with that solution is that it would require disassembly to remove the arms.
It would be good to hear how these solutions actually work in practice.