Google Admits To Accidentally Collecting Personal Data With Street View Cars

Excuse me, Mr. Kincaid, how exactly do you automatically assume that

But it’s now clear that we have been mistakenly collecting samples of payload data from open (i.e. non-password-protected) WiFi networks, even though we never used that data in any Google products.

is synonymous with personal data, given the massive amounts of data that travels the airwaves between wireless access points and network devices, anything ranging from device identification to protocol addressing? Secondly, it's not as if this isn't a casualty of running an unsecured wireless network.