Was in the air a couple of years back during the US East coast blackout flying to Toronto. We got diverted to Montreal and after an age on the tarmac got into the terminal.
After picking up my bags, headed over to the car rental zone. I was lucky enough to get a car as there was only a few left and by the time I finished the paperwork the counter reps were turning people away.
Given the situation, I ended up giving two other passengers a lift to Toronto (couldn't take a 4th due to luggage constraints).

We checked out the lots of the other Rental companies as we drove past & they were all virtually empty.
Unusual circumstances obviously but I'm guessing there was a lot of one way rentals & it took a few days of reshuffling to get things back to the norm.