Edit: mystery's solved, OP's edited with how it works. Note: this should work on all versions.

If you incapacitate the bots on the Dark Carnival finale they will get kicked when the sound stage is activated. This will work as long as they are not in the back of the room.

This will persist after campaign changes, given you call a vote to change it. The map command will simply start a new 'game', nullifying it.

This is mainly helpful for the Dead Center and Hard Rain first chapters, where you only have pistols to incap the bots. It also shaves off several seconds every chapter due to not having to incap (and damage) them.

The direct map change is relatively useless in solo runs, as not having mouse control makes it difficult to shoot the bots. Only Swamp Fever benefits from it fully, so I recommend doing it last.

Here's an example, at 10:00 (can't be assed to edit the video) I didn't realise they were gone until I switched to The Parish.

As a sidenote, Dead Center finale could possibly be pretty annoying without the bots crowd controlling as you collect cans.

this would cause some problems(if people decide to set up macros with the "kick x"), im going to say that any runs with that bug would require to submit the console log(the whole log) to prevent any abuse.

Since there is no other way to "prove" the kick command was not used, this sounds fine to me. I don't think L4D2 saves anything in terms of logs, so I guess showing the console after the bug is performed will have to do? This will pause the game, though.

If all person can do that on this version it's too broken so i'm gonna see if that do the same bug on the 2.0.2.7 btw Maybe i gonna add a new version and when i said that i'm not sure because i'm gonna test the 2.0.2.7 this version look like better than the 2.0.0.8

Not RNG, not dialogue. First try. Let's play spot the difference!

Thanks for taking the time to read the OP. Oh wait...

You're welcome.

I believe this works in the current version as well, but it might be patched because it's been so long since I've played the mutation or had anyone in there.

When you start the finale it causes the garage door to the starting area to close, preventing survivors from going back in. I don't believe you can start the finale unless all survivors out outside, with the exception of possibly bot survivors or maybe incapped survivors?

It affects anything inside the arena though. It kicks the entities that are still inside the structure once the garage door closes with some weird steam message error. It was very quickly discovered in the mutation Taaannnkk!. As the Survivors got a headstart to leave the saferoom before Tank players would randomly get spawned on the map (Sometimes at saferoom). I had the misfortune of being spawned at saferoom right before the survivors activated the finale and I got kicked from the server with some weird error message.

Anyways, it's not RNG. I'm not even sure it's a bug but a poorly designed feature to prevent anything from getting stuck/spawning inside the structure.

EDIT: Also, have you tried the "changelevel" command instead of the "map" command? I believe changelevel causes things to persist through, including modified CVars. NVM, doesn't persist the bot kicked.

Thanks for the info. I tested it numerous times and this does seem to be the case. However, there's a range to where it will work, which was throwing me off.

As long as the bots are not in the back, behind the red line, it works. I'll edit the OP.

so if some1 is doing an IL can they just do this glitch in advance and then proceed to get free time on the level they choose?

No.

I found some more (useless) information on this via Google: http://forums.steampowered.com/forums/showthread.php?t=1818615

The error was: Disconnect: Kicked by Console : CBaseEntity::InputKill().

While my partner and I were running last night Mawfeen was in my stream and informed me of this bug. We are currently playing on the most recent version and I can confirm it works just the same there. Very handy when doing a full game run without four players!

As for the debate earlier on about people being able to kick the bots and abuse it, what's the difference? It is very obvious that this bug is being executed, you can see where they are incapped and they are always kicked as the finale starts. There is no other way to kick them that wouldn't be immediately noticeable since this bug is so specific.

That discussion was before we figured out how it works.

Understood. Guess I was a bit late to the party.