A health-care company tried to block workers from jumping to a competitor. They failed.

Usually, when the topic of “at will” employment comes up in this column, it’s in the context of explaining how employers can fire an employee at any time, for any reason that doesn’t break the law. But with the current job market tilting in workers’ favor, we’re seeing more of the employee side of the at-will coin: Unless you work under a contract or in a state that imposes certain exceptions, you are generally free to leave a job for any reason. And during the coronavirus pandemic, employees have been doing exactly that — for their mental and physical health, for better pay, for a fresh start.