I was a GCFTW regular for a long time. Haven't played regularly in months, joined today, promptly banned less than 30 mins into my game session. Was not warned at any point that I was being banned. I do not rush, I do not swear. I may have been using the voice coms but I didn't think it would be considered spamming. If it was for that reason, I will unbind the voice com key (as nice as it is to communicate with the team as someone without a mic). Also, I will refrain from using it as such.
Added information to help:
It was on L4D2 server #1
In-game name {GbK}Cobb
SteamID: STEAM_0:0:2850796