[ghost of evilspy]

I don't trust Valve, something I learn while coding C-D.

This doesn't open any new ways to cheaters, it's just server side modification. Only real danger is that some people start running servers that show completely false information about server outside, like almost full server with players been online 30-120min + score alerted without using ingame fakeplayers. And modification doesn't even require code modified on server, it could be done on router of malicious server operator by simply alerting right packets (which are very easy to detect since HL1/Source don't use any encryption of server query protocol).