Thanks for posting how things went for you. Based on my own experience, and what I've read since Friday I'm more and more convinced that this 'Activation' page is primarily a device activation to prevent scalping. It also has a side benefit of being able to activate a new SIM card in place of an old one to generally make the upgrade process smoother for 90% of the people out there. I say side benefit, because if this were truly the only or main purpose, Apple would provide a simple way to bypass the whole thing on the device itself by tapping 'This isn't my phone number' and letting you into the iPhone anyway.
I suspect that, similar to the carrier account wall when ordering the phone this 'device activation' part is primarily on Apple's end, and very little actually occurs on the wireless carrier's end. I have two more 7s coming, the next one should be here Wednesday based on the tracking info (although it seems to have been stuck in China for the last 3 days...) For this phone I intend to install my AT&T SIM card and use my AT&T data connection to provide the same VZW account info that I used to order the phone. We'll see. I also wouldn't be surprised if no SIM card installed, WiFi for data would allow you to activate the device, as long as you have the VZW account info provided at time of purchase.
I also suspect that the only time the carrier gets involved, other than to validate the provided account information is if you 'device active' with the new SIM installed that ships with the device. In that case only, then some magic happens on the carrier backend to activate the new SIM card as well and de-activate the old one.
I'll post back how things go with the next phone later this week... In the meantime, if anyone manages to screw up their friend's wireless account please share how you did it so the rest of us won't make the same mistake