You are right to call this mess a 'battle'. Each of us who has received the official notice from Infiniti are on the same sinking ship. And trust me, no matter who is in the car and where they are seated, they are ALL at risk of horrible injuries should your car be one of the very small number with exploding air bags.
Back to your question. I have contacted attorneys and done my own research and there is NO actual 'legal' requirement that your dealer provide a loaner vehicle or even arrange a third party rental vehicle while waiting on the arrival of parts, or while repairs are made.
That doesn't mean you cannot demand one or that you cannot file suit to get one. However, there is a reality that what is 'fair', what is 'morally right', and what is 'legal' are very different things. Personally, I see no point in perusing any legal actions. The auto makers have armies of lawyers who will make sure your case never sees the light of day.
At first, whenever Fetucini (the Mrs) and I went for a drive together, she would sit in the back. I also have a milk crate with some books in it to keep the passenger air bag in the OFF position. Later on we both worried that it really doesn't make her (or me) any less likely to be injured. Luckily, we have an SUV and if we are going to dinner, or out for a drive together, we use the SUV. I still drive my M, but only because I firmly believe that my car is NOT one of the very few with a problem (no facts to back that up, it's just how I feel). However, I would never knowingly place anyone else in danger albeit my wife, our friends, or even strangers. Therefore, the M is only driven by me and alone with the milk crate on the passenger seat. In all other cases, we use the SUV.
I posted a thread about the recall and what I was able to confirm back in August:
topic610369.html?hilit=air%20bag
The most reckless part is that Takata (the manufacturer) is replacing our air bags with the same faulty, risky propellant that is now under recall but with an added drying agent that 'should' reduce the breakdown into an actual pipe bomb like the one some of us have in our dash.
The good part is that, after repairs are made, it will be years before we are again at risk and with any luck, we will be driving a different vehicle and our current Ms will be in a junk yard where they cannot harm anyone.