It's "physically impossible for Google to read the IP header addresses if the pack data contains "&aip=1"? The IP is still logged with Google, according to their own documentation[1]:
When present, the IP address of the sender will be anonymized.
So-called "anonymized" data can be re-correlated with the original values. DJB's gave a great description[2] of this problem, right after he started working for Verizon[3]: Hashing is magic crypto pixie-dust, which takes personally identifiable
information and makes it incomprehensible to the marketing department.
When a marketing person looks at random letters and numbers they have no
idea what it means. They can't imagine that anybody could possibly
understand the information, reverse the hash, correlate the hashes, track
them, save them, record them.
[1] https://developers.google.com/analytics/devguides/collection...[2] https://projectbullrun.org/surveillance/2015/video-2015.html...
[3] If you don't believe that DJB works for Verizon, ask the man in the middle... who may have been making an elaborate joke.