The author has extrapolated their experience in (at most) a handful of airports to the general case.
One of the first projects I was given as a junior engineer was to measure signal strengths of our and competitor mobile networks at the local airport. This was pre September 11, but I was still amazed at the access we got carrying a signal analyser and just flashing our employee badges got us.
For inbound roaming users, absent particular partner network preferences (which were less common back then), the mobile device would select the local network to use based on relative signal strengths when turned on. Capturing those inbound roaming fees was a high priority for the product managers and hence a lot of effort and infrastructure investment went into this.
One of the first projects I was given as a junior engineer was to measure signal strengths of our and competitor mobile networks at the local airport. This was pre September 11, but I was still amazed at the access we got carrying a signal analyser and just flashing our employee badges got us.
For inbound roaming users, absent particular partner network preferences (which were less common back then), the mobile device would select the local network to use based on relative signal strengths when turned on. Capturing those inbound roaming fees was a high priority for the product managers and hence a lot of effort and infrastructure investment went into this.