[randomdata]

> employees have no leverage

Amazon's job ad for "Warehouse Team Member" at that location indicates pay 30% above minimum wage plus benefits. That suggests the workers have a reasonable amount of leverage. After all, why would Amazon pay anything more than minimum wage if the workers had no leverage? There is nothing to suggest that Amazon operates as a charity.

> are easy to fire

Not when one is being fired over taking necessary precautions to serve their health and wellbeing. Ontario labour law does not take kindly to that in the slightest. In fact, Ontario regulation requires employers to make that known to the employees, so it isn't even a case of "He didn't know." The, as summed up by the popular TV show based on the nearby town of Listowel, "When a friend asks for help, you help them" explanation is the most likely. It is the Canadian culture to be compliant when someone asks something of you.

[Alpha3031]

There are proposed microfoundations for efficiency wages that do not necessary imply a significant level of bargaining power for an individual worker.

[randomdata]

Even if that were true, individual bargaining power is irrelevant here as the workers share a collective agreement that clearly asserts that Amazon will not terminate employment for reasons related to safety.

Logically, the workers knew there was no onus for them to leave their cars. But when your friendly coworker comes along "I know it is warm in there, but can you please come outside with the rest of us who don't have the same luxury?" it is hard in Canadian culture to say no. Rather you get "Sorry. I'll be right there."