Fortunately for us all, the justices decided that egregiousness largely means malice and recklessness. It can mean that an employer must realize the risk that unlawful discrimination will occur. There is enough in this definition of egregiousness to keep employment lawyers gainfully employed for decades. Employers fighting off punitive damages, said the justices, have defenses. One is that the company wasn't aware of the federal prohibition.
Ignorance is bliss.
Then the justices expect cases in which the employer believed discrimination lawful. The reason for discrimination may be novel, or the employer may think, mistakenly, that discrimination is necessary for a bona fide occupational reason. After all this work, the Supreme Court didn't really decide whether the ADA's actions were egregious. Rather, it decided to remand the case to the trial judge to find out, according to the rules that the justices spelled out. Justices on their own questioned whether ADA, as principal, could be liable for punitive damages stemming from discriminatory acts of its agent.