The Golden State Warriors are facing a tough showdown—not on the basketball court, but in a U.S. district court, where a judge has ordered the team to trial over its smartphone app, which allegedly recorded fans’ conversations.

The Warriors’ app bills itself as a way for fans to keep track of scores and stats. But while fans were watching the game, the app was watching them, fan LaTisha Satchell claims in a lawsuit. One of the app’s promotional tools allegedly turns a user’s phone microphone on and keeps it on, recording everything within earshot and relaying data back to the Warriors and a tech company, possibly in violation of wiretap laws.

“[The Warriors] gained access to tens of thousands of microphones belonging to consumers who downloaded the Warriors App and turned their mobile devices into bugged listening devices,” the suit alleges.

The unlikely snooping program started as an effort to sell merchandise and ticket upgrades, the suit contends. The Warriors wanted to know when fans were on Warrior-owned property, and how long they stayed there. The app tracked this through audio “beacons” that played through special transmitters in their arena and stores, the suit alleges. The app listened for those beacons and sent customized advertisements to a user’s phone.

An app user sitting in the nosebleed seats at a Warriors game might get a notification suggesting they upgrade to tickets with a better view. A fan in the gift shop might get an alert about a special promotion on merchandise.

The Warriors’ technology partners said fans were fine with the notifications.

“You’re not going to get mad at the Golden State Warriors and go to some other arena instead,” the CEO of the company that installed the beacons told Bloomberg earlier this year.

But the app allegedly didn’t stop when fans left the arena. Instead, it constantly listened in and recorded conversations, even when fans weren’t directly using the app.

Satchell first filed her suit last year, accusing the Warriors of snooping on fans’ conversations. But a judge slapped down the suit, claiming Satchell didn’t provide enough information about the conversations the Warriors allegedly recorded.

In an amended complaint filed earlier this year, Satchell described the personal information the app could have intercepted, including conversations with her husband in their bedroom, private business meetings, and discussions with a loan officer.

During all these conversations, Satchell had her phone within earshot, which means the app was recording through her microphone she says.

The app funneled data back to computer program, which let analysts monitor users’ actions, the suit claims. The suit includes a screenshot from the Warriors’ data-tracking platform, which shows a graph of how long 2,178 app users stood in a single location in or near the Warriors’ arena. (The average user stood in that spot for one minute and 25 seconds.) The data-scraping program could be tailored to track a user’s “in-location customer path,” the suit claims.

Users likely didn’t know the app was monitoring their locations and listening in through their microphones, the suit alleges. When Satchell downloaded the app last spring, it asked users for permission to use their microphones, but did not suggest that the microphones would be running in the background, or used to track location, she says.

And even if users didn’t want the app to use their microphone, they would have to turn off the app’s suggested settings.

“Because beacon tracking is inherently invasive (consumers are continuously tracked), industry standards dictate that consumers opt-in to beacon tracking,” the suit claims.

On Monday, a U.S. District Court judge in Oakland said the alleged recording might have violated the Wiretap Act, which bans real-time interception of phone calls or, in this case, conversations made near a phone.

The app, which has as many as 500,000 downloads, according to the lawsuit, is still available in app stores. But now the app’s installation page offers a semi-explanation of its controversial tracking software.

“This app utilizes beacon, Bluetooth technology and location services to enhance your fan experience,” the message warns. “Enable Bluetooth and accept location services to receive certain info and promotional messages.”

The average user, however, still might not understand what they’re handing over.