screen names be careful with addons in L4D2 even if the server prevents users from using an addon lets say the server prevents the "see through walls" addon
people who really want the "see through walls" will still get the "see through walls" you cant really prevent it people like me have been trying for 7 years without success
just refer yourself to this YT video for more
https://www.youtube.com/watch?v=Oz61Ud65MiQ