The fix shouldn't be to make your config read only and restart the game every time this happens. Guess what? The server forces cl_allowdownload to 1 before it starts downloading the sounds. I don't want to download annoying sounds from servers, and I am setting cl_allowdownload to 0.
Servers can even open/close the players cd tray with the 'cd' command. It's quite annoying to join a server and find out that all of your binds have been changed, etc. It's been known since a long time now that admins are able to send any commands to the clients, thus mess up their config. The following commands are blocked from a server running them on you if cl_filterstuffcmd is set (some are always blocked right now also) Alfred here, adding the list of filtering rules to the top of this bug so we can all track/understand the changes>
