How it works: Federal law allows employers to charge higher health insurance premiums to workers based on a health factor only if that factor is within a “wellness program,” according to Georgetown University health insurance expert Sabrina Corlette.

Yes, but: “Most [wellness] programs do not work,” health policy researchers wrote in 2017. “Some raise serious legal concerns.”

Delta’s surcharge may not follow federal guidelines.

Penalties can’t be so large that they’d be “coercive,” according to the Equal Employment Opportunity Commission.

Rewards and penalties in a wellness program also can’t exceed 30% of the cost of employee-only coverage, which in 2020 averaged $7,470, according to the Kaiser Family Foundation.

Delta’s $200-a-month penalty, or $2,400 for the year, exceeds 30% of that average and would more than double the average worker contribution. Other companies have been contemplating much lower surcharges.