What kind of compensation can you receive after suing a car rental company that compensates for the difficulties you have endured when told, no cars available.
First off, any money that you were out because of the lack of car provided. Cost of taxis, ubers, etc. Forfeited hotel or plane reservations. Those kind of damages would likely require receipts. But there are also the intangible harms--events missed, days of vacation time wasted, etc. Like pain and suffering, those intangible harms can and must be reduced to a monetary sum--depending on the circumstances and what you can persuade a small claims court judge to award given them.
It doesn't matter that it might not be Hertz' 'fault' that they didn't have a car available. They knew that they were having serious car shortages and continued to take and confirm reservations that people relied on, and their reliance on the confirmed reservation caused them harm. The rental companies could easily have changed their websites to reflect the situation that they fully understood, but customers did not. That's why they should lose.
As for any arbitration agreement in the relationship with Hertz, there may be two reasons why it won't bar recovery for victims. First, it's an affirmative defense to the complaint which has to be raised in small claims court by Hertz, which means they'd have to appear in person to raise it. And they probably won't and will simply default. Second, for it to bind the consumer, the consumer has to have notice of it at the time that they make the reservation. Is the existence of an arbitration requirement provided at the time of the reservation? (I'm too lazy this morning to make a pretend rental to find out, but I don't recall seeing one in previous rental reservations.) My guess is that the arbitration clause, if it does exist, is in the fine print in the form the consumer gets when checking out the car. Since that won't happen when you don't get the car, it can't be enforced in the case of non-delivery of a vehicle.
So as not to hijack this thread any more than I have, let me just say, in my final word on this, that I am a real believer in small claims courts as a mechanism for speedy justice. Depending on the jurisdiction, the amount claimed can be substantial--up to $10,000 in my state of Washington. Too many people simply feel forced to walk away from situations where someone else wronged them because of the time and expense of filing a lawsuit, so the wrongdoer gets away with it. Small claims court was designed to provide a way to get legal redress without the delay and legal expenses of ordinary liltigation.