If you are going to stop Zombies from entering your community or your property, you are going to need walls, fences, and gates. However, too many gated communities lack full fencing around the property, lack proper walls, and even lack a sufficiently strong gate.
A gate does no good if Zombies can push it down or walk right around it. If you are going to buy a house or rent an apartment, make sure that the gate is strong enough to be worthwhile obstacle. If it isn't going to stop intruders or stop zombie hordes, why pay for it?