On Dec. 18, the Dallas Mavericks will host the Phoenix Suns in what will likely be an inconsequential mid-season affair between two sub-.500 teams. Even so, tickets to the game will probably sell out, just as they did for 719 consecutive Mavs home games leading into this week. The Mavericks, who are in last place in the NBA’s Western Conference, have a longer active sellout streak than any other professional basketball team. But that distinction also raises some eyebrows — after all, by all reasonable accounts, Dallas is not a team that people are clamoring to see in person.

This season, the Mavericks boast the highest attendance rate in the NBA — average attendance at Dallas games is 102.8 percent of the capacity of the American Airlines Center (19,200). Based on attendance numbers alone, you’d think the Mavs would be better than their 7-20 record.

In something of a paradox, the Mavericks also have the league’s worst road attendance rate — meaning that they are objectively the least interesting team to watch to the average basketball fan who doesn’t live in Dallas. The average attendance when the Mavs are the road team is 86 percent of capacity, which gives Dallas a nearly 17-percentage-point gap between its home and road attendance rates. No other team has as large a gap — except for the Atlanta Hawks, who have the opposite problem. The Hawks’ road attendance rate is 17 points higher than their home attendance rate.

The difference between the Mavs’ home and away attendance rates could be seen as a sign of how diehard their fanbase is. But here’s the thing: NBA attendance is measured in how many tickets are distributed, not how many are redeemed. A more accurate interpretation of the situation is that Mavs tickets aren’t selling out so much as they are being given out.

“It’s far more important to me to build a fan base for the future,” Mark Cuban, the owner of the Dallas Mavericks, said in an email. “And the best way to do that is to get people to a game.”

You might think that a bad season would threaten the sellout streak. Last season was the first time since the 1999-2000 season that the team finished below .500, and Dallas posted their lowest local TV ratings in at least 11 years. And yet attendance has remained at or above capacity for every home game since Dec. 15, 2001.

Cuban cites two reasons that games have continued to sell out: pricing and donating.

Compared with other teams around the league, the Mavs are one of the most affordable teams to see in person if you don’t mind sitting in the nosebleeds. A ticket for a Dallas game at home in the upper bowl this season costs $30, on average, at StubHub, a seller on the secondary market — which is a better barometer of supply and demand for individual game tickets That’s less than half the average price of an upper bowl ticket in the NBA ($63).

But one thing that has helped the Mavericks to extend their sellout streak is the number of tickets that are donated to schools and charities. “For slow games, we will use our community service group to proactively invite groups to a game,” Cuban said. If a game doesn’t sell out on its own, the Mavs can donate the remaining tickets and still call it out a sellout. “Tickets are perishable,” Cuban said. “We feel like having a seat full with a young fan creates a Mavericks fan for life. It’s an investment in building our future fan base.”

Cuban said the sellout streak is not all that important to him, but he also recognizes that it is important to his organization’s sales and community groups. “They know I care far less about the gate than I do having a full house,” said Cuban, who said ticket sales have been making up a shrinking percentage of the Mavs’ total revenue in recent years as other sources of revenue have risen (e.g., national TV revenue and sponsorship sales). “So they have carte blanche to put ‘butts in seats’ over revenue.”

Although it’s not entirely accurate to call it a sellout if the unpurchased tickets are given away, it’s difficult to criticize Cuban and the Mavs for their charitable work. Because NBA attendance is measured in how many tickets are distributed and not how many are redeemed, the Mavs will hold the record for the longest active “sellout” streak for as long as they want.

Check out our latest NBA predictions.