Yes, I call BS on the wireless router explanation, too.
My wife and I bought HTC Trophy phones at the same time.
Wireless sync on my phone worked. Wireless sync on my wife's phone worked. Both use the same wireless access point.
But then, about 15 months later...
Wireless sync (but not WiFi Internet) on my phone stopped working. Wireless sync on my wife's phone still works to this day. Both still use the same wireless access point.
I have had 2 occasions where, out of the blue, Zune woke up on my PC while my phone was charging and
tried to sync wirelessly, but failed. Even that hasn't happened in a few months, though.
The problem is either my phone, or my computer, and someday I'll try setting up sync for my phone and her computer, and/or her phone and my computer, to isolate the cause. Uninstall/reinstall Zune & the phone drivers on my computer didn't help.
But the evidence conclusively proves it absolutely, positively, CAN NOT BE my wireless access point.
Very frustrating. For me, Zune is the "killer feature" of my Windows Phone and it's orders of magnitude better when wireless sync can change up the songs stored on the phone at every charge so I don't hear the same music over and over until I connect it
to my computer. (Yes, a first-world problem to be sure.)