After I got my thousand points for the gold, I stopped doing it unless someone pissed me off, or was just a totaly oblivious sniper. The hit detection at times in 2142 for knifes seems worse then in bf2, which I did not think was ever earthly possible. If I was prone behind someone in bf2, *occasionaly* i'd get the knife sound but no kill. 2nd shot, he's done. I've gone as far as 4-5-6 times and it not kill someone, when neither of us are moving.
Dogtags deffinetly help keep the K&P servers active... and EA themself proved you can even have a thousand double dog tags, and not get reset for suspected padding (noobish-noob). If I remember correctly, vegence's stats weren't even that stand-out-ish in bf2 when he got reset.