okay, i jsut came across this topic, and figured i would chime in.
Basically, after feb 2013 cs 1.6 updates, my pug would always get svc_bad errors, or something similar on that context.
I think this happens when engine/plugins try's to send messages to players that it thinks is connected, but in reality, they might have lagged out/disconnected etc and then it freaks out while trying to send that message. engine messages such as night vision toggle etc used to crash server, or kick half the server out.
this could be also a plugin issue, that is coded badly, and does not check if player is connected before sending messages to him.
by simply adding
reduced 90% of svc_bad errors for me atleast. some people said to put 3 seconds, but I think that is too little, incase if a player's net connection drops for a second or two.