I agree with Tejeretics and RationalMadMan. Too add on some points through:
Firstly, "noobsniping" is more damaging against an active opponent geniunely interesting in debating then someone who logged on once and never came back. The policy of forfeits being null debates doesn't help novice debaters, which is what I'd think your policy was aiming for. I had to debate bsh1 one time on DDO, and it was when I was a complete newbie, but admittedly I punched down my weight too, to establish sone credibility.
My big issue is that its incredibly unfair to the debater that didn't forfeit to have been cheated out of ELO. Even on forfeit debates, you need to post arguments to win the arguments category. This includes full forfeits since there is jo benefit of hindsight that a skilled debater wasn't just busy. Writing up these arguments takes considerable time, energy, and data. When I started my Joffrey debate, I had to watch hours of Game of Thrones and analize scene by scene, and that ended in a full forfeit. It was extremely unfortunate someone accepted and proceeded to full forfeit, but the ELO was compsensation. Why should someone who spent hours formulating an argument lose out on both the enjoyment of argument and the potential ELO? Its an incredible waste of time and energy, and one that was totally unwarranted. If anything, the ELO penalty that used to come with forfeits punished someone who ruined a good debate people spent hours on planning. ELO should be given as a compsensation, especially when considering the unfairness of the situation; the non-forfeiter didn't do anything to cause a forfeiture, and doesn't even have much tools to ensure a nonforfeiture.
In conclusion, making forfeit debates not worth ELO doesn't benefit anyone, but hurts debaters who have personal time invested and no control of the opponent's debates. Its incredibly unfair to an active debater, and doesn't actually protect new members. Tejeretics and RationalMadman gave some up arguments too; but I feel like these two are other glaring weaknesses of the policy.