kotaku.com/5455199/left-4-dead-2-adding-...ts-axing-auto-spawns
From Kotaku:
"Valve's "L4D Team" writes on the official Left 4 Dead blog that the developer "adding bots for the Infected team to help out the Infected when they are down a man or two," a change that should make lonely Hunters and Smokers happy.
Another forthcoming change that should make the Boomers out there happy is the impending removal of auto spawn. Don't you hate that? You've got a good finale going, spawn automatically as the Boomer or Spitter, with no cover between you and the Survivors... well, good riddance, I say."