I've got you beat, because I've logged on and received actual kills just like that. Twice. Once in AHI and once in AHII, I think. Unfortunately, as is always the case, I can't prove it. But it always entertained me.
I thought it was due to the old "walking around" system. Not many people ever noticed it, but AHI had a slider in the settings called "movement speed" that defaulted to maximum. However, if you moved it all the way to zero, any time you moved positions on the ground (Tower, Hangar, Map Room, O'Club[can't remember if this setting survived this shift to AHII for a while], even between bases), it revealed that your "camera" actually "walked" there manually...you'd turn, walk out of the tower, down the stairs, then to wherever you were going. Which, of course, meant hours of walking if you were changing bases to the other side of the map. Even with it maxed, if you moved a very long distance and watched closely, you could see one or two frames of yourself running there.
Putting this together with the "everybody seems to spawn into the 10,10 sector when logging in" bug, I thought maybe I was getting proxies as my character uber-ran between 10,10 and the base tower.