She was spotted smoking in ‘smoke-free’ rental housing. Now, she may be kicked out.

Advocates warn that enforcing these bans too aggressively — such as with the threat of eviction — could add to the hardship of vulnerable communities that have disproportionately higher rates of nicotine addiction, including people who live under the poverty line, people with mental illnesses and the elderly.

“To let people buy an addictive product, to actively advertise it to them, and then just to say ‘Don’t do it’ is to not understand the social reality of what it means to smoke,” said Harald Schmidt, a professor at the University of Pennsylvania who argues that curtailing employment opportunities for smokers is ethically unjustified.

In offering landlords the option of eviction, the HUD ban may have opened another pathway for tenants to enter homelessness, harming instead of benefiting public health, Dave Fagundes and Jessica L. Roberts, law professors at the University of Houston, said in a recent essay. The policy, they wrote, “poses unappreciated distributional concerns, with the heaviest burdens falling on historically disadvantaged populations.”

When HUD introduced its ban in 2016, then-Secretary Julián Castro told reporters, “The last thing that we want are evictions.” But nationwide, individual public housing authorities and property management companies oversee evictions, often with a great deal of discretion, said Bridgett Simmons, a staff attorney at the National Housing Law Project.

“Enforcement is going to vary,” Simmons said. “Some management staff will see an opportunity to get rid of a tenant they don’t like and seize it. Others will be more sympathetic.”

Advocates say they have heard of several lease terminations since the HUD ban took effect, although a department spokesperson declined to respond to inquiries about how many violations there have been or how many of those violations, if any, have led to evictions.

“Essentially, we know very little about these bans because there are no reporting requirements,” said Schmidt, the Penn professor. “It’s very frustrating.”