It's only an issue because they measure data consumption as a part of their billing infrastructure, and to determine if subscribers have exceeded their monthly allotment. Their ToS also prohibits the use of their non-commercial services for commercial purposes. So, I think they're within their legal right to investigate my data useage if I exceed certain thresholds, which I most definitely did. 

An individual subscriber who uses nearly a terabyte of data in one month is bound to raise questions. They weren't interested in the details of my use, only that I was only using the service for personal use. I chose to establish that by describing the devices I was using, and attesting to the fact that I was using the data exclusively for personal use. That's as far as it went. I invited them to contact me if they needed any further information, and they never did. So, it's case closed.

In general, I don't think they do this regularly because I've asked all my Verizon friends and family if they've ever been investigated for their data use, and not a single person had. So, I was an outlier due to my admittedly unusual data consumption.  

 It isn't a market if it requires identity and policing. TollGates charge for megabytes used and/or for time because those are more fungible than government usernames.  

 We are likely to find that 1TB of data is cheaper on the free market than on the KYC subscription.  

 If you can point me to service that provides unlimited broadband + unlimited voice + unlimited text for less than $145/mo with no additional or upfront expenses, I'll switch tomorrow.