players are spawning with 3 snowballs in their inventory, and I didn't see any config or part of the CS file that you could prevent that with..
Player are spawning with snowballs
That is dafault, thats what Christmas event does. You also dont need a mod to do this just type "xmas.enabled true" in your console.
Also check out "StartUpCommands" mod, it will run the command on server start. So even after a restart it will be CHRISTMAS!