My family just started a new family plan, and I'm still waiting for my phone.
But the AT&T rep waived all 4 of our activation fees, even though only 3 lines are currently on the plan (until my iPhone comes in)
I called asking to unlock our registration for the online account, and I just kindly asked her if there was anything they could do about the activation fee. I simply said we just bought 4 phones, and signed on for 2 years, and was hoping they may just do it in good faith.
The lady said she wanted to start off our relationship with them on a good foot, so she said she would waive all 4 of the fees and credit our account. She also changed the caller-ID names for the other 2 phones, so when my sister or my mom calls someone, the caller ID doesn't show my dad's name, but their name instead (which has always bugged us)
It doesn't hurt to simply ask. She says they've been receiving calls non-stop. Just be polite and patient and you may be able to save some money!