The proposed 18-month pilot could cover some or all U.S. District Court locations in Denver, Colorado Springs, Grand Junction and Durango. Visitors covered by the policy would keep the pouch with them but could not open it to use their phone until leaving, unless a judge permits access.

The proposal, announced Oct. 20, was put forward by the U.S. Marshals Service, according to court Clerk Jeffrey P. Colwell. The court says the program is intended to address phone use that violates longstanding bans on recording, photography and video inside courthouses.

Colwell said the court has received reports of members of the public using phones in courtroom galleries, hallways and at the clerk’s counter. He declined to give a total number of incidents, saying the court had seen enough to consider the measure prudent.

The court says unauthorized filming could expose witnesses, jurors, law enforcement officers and court staff to intimidation or online doxxing. Recording security features, such as camera locations and officers’ posts, could also create risks, Colwell said.

Lawyers, people representing themselves in court, journalists, law enforcement officers, jurors and people attending naturalization ceremonies would be exempt, along with other categories. The proposed notice also warns that the pouches’ magnetic closures could interfere with medical devices. Colwell said courthouse security would consider medical exceptions individually.

Jeffrey A. Roberts, executive director of the Colorado Freedom of Information Coalition, said the proposed media exemption matters because journalists use phones to take notes and communicate with newsrooms. He also raised concerns about whether visitors would have timely phone access in an emergency.

The 10th Circuit Court of Appeals, which has a courthouse across the street from the district court in Denver, has not encountered phone-use problems that it considers a security threat, court executive Leslee Fathallah said. She noted that the district court faces different circumstances involving jurors, witnesses and criminal defendants.

Under the proposal, visitors would keep their phones in the pouches rather than leave them in entrance lockers. Colwell said lockers would not prevent powered-on phones from making noise and could lead to lost or mistakenly taken devices or damage claims.

The court plans to compare reported phone incidents during the pilot with prior numbers. Members of the public can submit comments by email to LocalRule_Comments@cod.uscourts.gov until 5 p.m. Nov. 16.