From a newer player experience, I will say that it's extremely frustrating at times to see new areas pop up in an area that myself or my alliance just worked hard to clear out. The "reserve the room if you want it to not turn into a newbie zone thing" works great for players at higher GCL that can sacrifice a lower RCL room, or dedicate a few rooms to specifically handle the reservations, but for players like myself who are still under 10 GCL, I can't honestly dedicate that time, energy or CPU to stopping an area from being blocked off.
Here's the big issue for me:
I would be better off leaving my area with all players currently occupying it alone then risk killing them and having them be replaced by someone I can't attack for 14 to 30+ days. At that point, there's little reason for me to fight anyone in any room since if I'm not able to immediately occupy it I run this risk.
Again, that may not be something that higher GCL players do or worry themselves with, but for me, I'm better off leaving the zombies in my backyards then risk an unknown player being able to set up camp there while I can't do anything about it (including expand).