But if you want to do the same test again, prior to docking on your own FC, land on another FC (or station) first, and see if you end up respawning there.
So i did that, no change.
PC-AspX docked at another carrier in the same system (Col 285 Sector VS-H B11-0), then docked to XB-carrier, then jumped to suicide in Col 285 Sector SS-S C4-22 (in the meantime i set docking deny on carrier), Boom! - respawn point was still Diaguandri
Next test:
Respawn at Diaguandri, jump to Umastae and dock to Isherwood Dock, jump to Col 285 Sector VS-H B11-0 and dock to a random Carrier, launch and dock to my XB-Carrier, go to suicide system, Boom! Respawn at my XB-Carrier (doh, forgot to set docking permission to deny!) Grrrr.
One more:
Respanw to my XB-Carrier, jump to Umastae and dock to Isherwood Dock, jump back to Col 285 Sector VS-H B11-0 and dock to a random Carrier, launch and dock to my XB-Carrier (set deny permission on XB-Carrier), jump to suicide system, Boom! Respawn at Umastae, Isherwood Dock. Finally!
And the last one: Same as above, but instead of going Boom in a system with no other Carrier/stations, I suicided in the system with my XB-Carrier (docking denied) and 9 other carriers (all open for All). Again I ended up in Umastae at Isherwood Dock.
So, I can only assume the Beta didn't record the last dock station and Diaguandri was a forced pick.
To conclude, keep in mind that the suicider was a visitor of the last_docked_carrier and not the carrier owner - and assuming no station exists in the Boom system:
If one goes Boom it will respawn at last docked carrier/station
If last_docked is a carrier and between the last dock and Boom the carrier denies docking, one will respawn at the previous station docked. Other Carriers are ignored in this scenario even if they are in the same system as the unfortunate killed pilot.