Have you ever heard that sound that car stereos used to make when a GSM cell phone was about to ring? It became less common over time because people started filtering those frequencies out explicitly on the “receiving” side as cell phones became more popular, but that’s an example of RFI that many people are familiar with.
We have a big library of hardware here–I’ve run into more than a few DACs that pick up similar interference from normal household stuff. One that is sensitive to a displayport monitor when it’s doing heavy screen updates…another that is sensitive to WiFi transmissions nearby, and so on.
This is without direct connection–and easy to hear by playing silence through the device, turning the volume up, plugging in headphones, and creating the interference.