"no smoke" servers?

[MadFF]

Hello all, I did some searches but didn't see a specific answer (and I am terrible at searching).

What is with all the servers that I see that have "no smoke" as one of their rules? At least it seems like a lot of servers.

What is it about the smoke?

Thanks.

[Wh33lman]

they're all coop server. its because the bots can see though the smoke and the humans cant. people throw smoke to try and hide but it only hurts the human players.

[MadFF]

Oooooooohhhhh.... I thought it was because people's computers were glitching with graphics or something.

Thanks!