It is what quiet airport means, at least in the context of SFO.

SFO's quiet airport policy is described on page 17 of this document: https://www.flysfo.com/sites/default/files/2025-12/2025-10%2...

Here are two quotations from that policy, directly relevant to the situation I described:

  "The playing of music is prohibited in the following locations: at the podiums, ticket counters, and seating areas adjacent to gates"

  "employees may not use mobile devices, including smart phones and tablets, in “speaker mode” in any public area of the Airport"