That's an insane proposition. Can't we make it so a certain area on each map at the spawn renders the zombies invincible until they leave it or something? Also that map would be Argentan. I have recently been improving and fixing it on Creative, and the original spawn was not meant to be in that house.
What why? 2-3 seconds will mean that humans will be afraid to spawnkill because of the fear of certain doom.
What's easier than slapping strength ten on the zombies for 2 seconds? It'd probably be easier than making an area around the spawn point where zombies are invincible.
Honestly nerf the kits. I believe that someone sent you a photo on spawn killing. Nerfing the kits will give zombies a better chance of killing humans. Don't make it a rule. Nerf it. You should get on infection and watch what happens. @SSMH and I saw it all yestrday.
Spawn killing is still an issue even with the immunity. At best it can be a kick, such as it is for block glitching.
A better but more expensive idea is to buy the people who spawnkill premium.Boom!Solved. Better yet,when they're spawnkilling.