Imagine a very, very large metal building with almost no "signal" inside. Furthermore, imagine three sets of restrooms placed in corners of the building.
One face of the building has an active loading dock where there IS signal.
Now imagine ERJ 35 feet up in the air with a birds'-eye view, watching workers walk to the farthest bathroom and catching up on their social media as they walk the entire width of the "hot" loading dock as close to the doors as they can get. They percolate through the baskets of material and double-stacked pallets of boxes that are staged for incoming trucks. Oh, and they have ear-buds in.