Americans who are highly motivated to get vaccinated are traveling across state lines after hearing about larger vaccine supplies or loopholes in sign-up systems.

Why it matters: "Vaccine tourism" raises ethical and legal questions, and could worsen the racial socioeconomic and racial inequalities of the pandemic.

• "People are getting anxious and frustrated with the system, and the system is how it is because there’s just not enough vaccine for everybody who wants it," Marcus Plescia, chief medical officer at the Association of State and Territorial Health Officials, said.

The big picture: Reports of wealthy couples taking private jets to Florida to get vaccinated have made national news, but Wendy Parmet, law and public policy and urban affairs professor at Northeastern University, said the problem is much deeper than a few ultra rich skipping the line.

• "If there’s not a lot of transparency and trust in the system, in its fairness and equity, then there are always going to be some people to game the system," creating a 'vicious cycle of inequity," she said.

What's happening: States like Tennessee that allocate doses by county population, rather than risk groups, forced essential workers to travel to rural counties with excess supply.

• Immunocompromised Louisiana residents traveled to Mississippi, where the state was prioritizing their illness.
• States are legally allowed to prioritize residents over visitors, asking for proof of address or a form of ID. The influx of "winter visitors" in Arizona caused Gov. Doug Ducey to request more shots earlier this year.

By the numbers: In the few states that are tracking out-of-state vaccinations, tens of thousands have been given shots.

• More than 30,000 people have traveled to Ohio to be vaccinated.
• In Florida, it's more than 82,000, not including part-time residents.

Yes, but: It's important for states to get shots to the people who may be less motivated to seek them out on their own, and when that require a broad brush, easing up on residency requirements may be worth it.

• "If you’re doing a mobile site in a hard-hit community, I wouldn’t worry about verifying residency at all. I think it’s at the larger scale sites maybe that makes sense while also giving an opportunity to access it somewhere else," said Govind Persad, a law professor at the University of Denver who specializes in health care ethics.

What to watch: More supply in the next month could also clear up some of these issues, Plescia said.

• "If you told somebody, 'We can get you a vaccine, it’s just going to be a week or two from now,' most people are probably going to wait for that. But I think some people are getting frustrated and anxious that it might be longer," he said.