The fallout from an incident last week on a United Airlines plane, in which a passenger was physically dragged through the aisle off of the supposedly overbooked flight, has led to executive apologies, customer outrage, and calls for passengers to boycott the company. But while many travelers have made public declarations of their intent to stop flying on United, either temporarily or permanently, the question of whether or not customers will actually carry out such a protest isn’t just a question of moral outrage. It’s also a question of economics.

For those flying economy, it seems that the two largest determinants of how Americans pick an airline are price and flight availability. Where does anger factor into customers’ calculus? A new survey from the polling and market-research firm Morning Consult explored the question of what it would take for people to actually boycott United.

The poll, conducted last week, presented several scenarios to the respondents in order to determine how and when they’d shift their buying preferences between United and American Airlines. For those who hadn’t heard of the United incident (about 30 percent of those surveyed), roughly half chose United when the flights and prices were identical. And when the hypothetical American Airlines flight was more expensive than the United one or included a layover, those who hadn’t heard about the incident overwhelmingly chose United—which, again, makes sense.

But those who had heard about the incident made a different calculation: Given the choice of two different flights between New York and Chicago that were the same price, 79 percent of respondents who knew about United’s debacle chose American Airlines instead. Even more striking, among respondents who had heard about the United incident, 44 percent would pick an American Airlines flight even if it cost slightly more (in the hypothetical, the United flight cost $204 and the American flight cost $270) and included one stopover.

Even if these scenarios were hypothetical, the results are telling. As economic theory predicts, those who weren’t aware of the United incident were mostly rational—preferring flights that were cheaper and reduced travel time regardless of which airline was selling the seat. For those who had heard of the incident, though, it affected their choices up to a point: When the flights’ prices and schedules were comparable, most consumers opted to boycott United. (Of course, some of them could have made this choice because they themselves were worried about how United might boot them from a plane.) For some, though, that preference shifted when United offered a flight $66 cheaper and the better option of a direct flight.

This sheds light on why some past promises of corporate boycotts never panned out: For example, while the #DeleteUber campaign seemed ubiquitous earlier this year, Uber remained the most downloaded ride-sharing app, showing that many Americans were still happy to continue giving their money to the company. Customers tend to have short memory spans when it comes to corporate scandals, but that’s not the only reason that boycotts seem not to stick. A lot of the time, the cheapest option wins out, making boycotts difficult to adhere to.

This may be particularly true in the market for U.S. air travel, in which many consumers lack good alternatives when faced with a fare or airline they don’t like. The United incident has shed light on the fact that many routes have been dominated by just one or two airlines, due to consolidation within the past decade. That is one reason why customers must put up with bad service when it comes to flying.

According to The New York Times, the researchers at Morning Consult plan on repeating the experiment in the following months. Those numbers may help show how long customers remember a scandal, and whether their willingness to inconvenience themselves for their principles wanes.