Yes, you don't "need" a real ID, but again, it is an example of the STATES doing the work for the FEDERAL government.... And again, this is all just as a double check for auditing purposes.
The government can simply say provide this on your yearly tax form. Place the current mileage reading from each of your vehicles into box #120. Input how many miles each of your vehicles has driven in the last year into box #121a. Input the weight of the vehicle into box #121b. Using chart #5a, lookup the multiplier rate for each vehicle and place that into box #121c. Multiple the value of box #121a and #121c and place that value into box #121d. Sum the total of all vehicles and place that into box #122.... And then if you get audited, they will send someone out and check the mileage values on your vehicles and compare against your previous years and this years tax submission, and note it to check against what you submit next year...
All the other things are examples of how this data is out there. It is in various garages and auto-shops if you took it in for a repair, oil-change, etc.. The registration data shows what the vehicles are, who owns them, the make, model, etc.... In other words everything needed to double check if you attempted to cheat. So you have a very high likely hood of being caught if you didn't simply fill out the form in the yearly taxes for the correct amount, and now are subject to the much greater crime of tax fraud with associated civil, and criminal penalties....