Earlier this month, travelers logging on to Charlotte Douglas International Airport's free Wi-Fi saw a question pop up asking about their preference in the upcoming presidential election.

The airport did not conduct the survey or see the results, spokeswoman Lee Davis said.

The question was for Google Consumer Surveys and came from a third-party advertising vendor at the airport, Cloud Nine Media. The survey violated airport advertising policy against using political questions, Davis said, and was immediately taken down once the airport learned of it through a media inquiry on Aug. 10.

At the time, Davis said, an existing Cloud Nine contract had just expired for running ads on the airport's Wi-Fi “splash page,” the introductory screen that spells out terms of Wi-Fi usage to get to the Internet connection. Cloud Nine had incorrectly assumed the next contract had been finalized when it launched the presidential question, she said.

“It was a timing issue,” Davis said, noting that the airport did not see the question ahead of time like it normally does. She was unaware of any complaints about the question.

Google Consumer Surveys rotates thousands of randomized survey questions so it is tough to say how many users were asked their presidential preference at the airport, Cloud Nine co-founder and CEO Sebastian Tonkin said in a statement.

He said the question was not tied to next week's Democratic National Convention in Charlotte, but was asked because it is a topic of national interest.

Survey questions are typically “very vanilla,” Davis said. Indeed, other Google Consumer Surveys questions range from queries about what people call a carbonated beverage (“pop” or “soda”) to questions about how much money dog owners would pay for organic cotton leashes.

All questions are optional.

Tonkin said Cloud Nine is revisiting how questions are presented to users so it is clear that the venue, such as the airport, has no direct ties to the question and no interest in the answers. Now that the San Francisco company is aware of the airport policy against such political questions, it will ensure that those questions do not reappear, he said.

On Cloud Nine's website under a picture of the Charlotte airport, the company says it gives advertisers the opportunity to reach a captive audience through Wi-Fi sponsorships in more than 6,000 venues, including airports, hotels, bars and restaurants.

The Charlotte airport has frequently run ads with its Wi-Fi service for several years, including for Google Consumer Surveys. But users can simply skip the questions and go to the splash page if they want.

The airport is now looking at its policies to see if any changes need to be made to ensure that this problem does not happen again, Davis said

Like most airports, Charlotte Douglas contracts for advertising with third parties throughout its facility. The Charlotte Regional Visitors Authority manages the advertising program for the city-owned airport.

The airport has offered free Wi-Fi for five years, and the popular service is used on average about 5,500 times a day, according to Davis.

At the moment, the airport does not have advertising on its Wi-Fi, Davis said, and there is no schedule for when it will return.

“We want to vet our policies and take our time,” she said.

That means the visitors who will soon be streaming into the airport for the DNC will not see any ads when they plug into the Wi-Fi.