My router is running MAC spoofing.
Playing AH is not like surfing pages on the net. It is a semi private client to server connection. The AH server would have to give you a hijack. I trust AH to keep it's systems clean. This is why I have no problem disabeling my anitvirus filters. During the game session I am only communicating to the game server. I'm not running anything in the background that communicates to other locations on the internet. I also won't allow my girlfreind to surf the net on her computer while I'm playing. I work for a company supporting windows based servers. At my site I support 850 NT, W2K, and W3K servers. We run into severe performance issues due to the number of filter applications required in our base builds. Microsoft at times has to create hotfixes just for our sites to account for memory bleeds exposed by the filters.
This is the reason for my concern about game performance impacted by running local filters while the AH client is connected to the server. Anything in your background processing that is competeing for CPU time is contributing to the rubber jacketing on your bullits.
Your ping time may never reflect this local competition. At best it might be that spit that you unloaded on and it flew away. At the worst it could be some of the frame stuttering you see in your game and can't figure out who shot you down.
In almost 2 years of playing AH, the AH servers have done nothing to my system but helped me enjoy a great game. I've gotten all of my hijacks from surfing web pages.