The fact that Microsoft chose to conform with the letter of this law is to be expected; rather, the fact that Google's lawyers somehow decided they didn't have to do the same is surprising, at least to me.
Curious though, I glanced briefly at the wikipedia article ( http://en.wikipedia.org/wiki/Communications_Assistance_for_L... ) and it seems mostly about hardware needing to be CAPABLE of logging, not always logging already. Can you explain your first statement?
To limit exposure under common carrier safe harbor, and consequentially insurance premiums, most ISPs maintain only sparse activity logs and flush those on a periodic cycle.
These policies may also differ radically due to compliance with municipal and state laws (CALEA is federal) and/or private contractor facilities where "sensitive, classified, etc." work is undertaken.
To use an analogy, the phone company doesn't/can't record your conversations on a routine basis, merely the initiating and terminating routes. Still, they must have the "capability" of complying with a wiretap's mandates if called-on to do so. Don't get me started on the "warrant less wiretaps" fiasco.
I suspect that Microsoft could just as easily have an open WiFi network, but fine-grained policies go hand-in-hand with their corporate culture. Some would argue that Google's course-grained policies create their own set of problems. For a similar example, look at how hardware provisioning and technical support is done at both companies.
Of course, any paid access immediately associates a name with an IP: the person on the credit card used to charge the access.
On campus theres some Wifi network that is open and unrestricted. The public access one has a public portal (and vastly lower coverage in Mountain View last time I checked.)
Microsoft also probably doesn't want employees to connect their personal devices the the guest WiFi -- very normal behavior.