Your Wi-Fi backup plan assumes cellular will work when the network fails. Have you tested that assumption? Most facilities treat in-building cellular as automatic redundancy. It isn't.
Two systems that happen to end at the same device
Wi-Fi and cellular use completely different spectrum, different antenna systems and different propagation patterns. One working in a location tells you nothing about whether the other will. Different coverage maps. Different dead zones. Different failure points.
The gaps show up at the worst possible moment
The operations manager making calls in the basement can't access the inventory system on Wi-Fi. The safety coordinator loses radio contact during an emergency evacuation and assumes mobile will cover it. It doesn't. In a hospital, the failover path carries clinical communications and duress systems, and an untested assumption in that environment is a patient safety exposure, not an IT inconvenience.
Mapped versus assumed
Here is the pattern we see most often. The operations team knows the Wi-Fi dead zones, because they live with them daily. Almost nobody has independently validated their in-building cellular coverage against the same floor plan. Two completely different propagation patterns, and the working assumption is that they align. They usually don't.
Cellular coverage in most facilities is assumed rather than mapped. Treating cellular as Wi-Fi backup without validating both is planning for a redundancy that may not exist when you need it.
Testing is a discipline, not an event
Failover should be tested during non-productive hours, on a schedule, the same way you would test a generator. Monthly failover testing is exactly the discipline most facilities skip.
One honest caveat: during a widespread outage, every device in the area is sharing the same carrier bandwidth, so congestion is a real constraint. That is another reason coverage and capacity need to be measured rather than guessed, and why hybrid designs matter for sites that genuinely cannot drop.
What validation actually looks like
Carrier-by-carrier signal measurement at the locations that matter, not the lobby. Cellular coverage mapped against the same floor plan as your Wi-Fi, with dead zones, degraded distribution infrastructure and capacity limits identified. Where coverage falls short, engineered in-building solutions: CEL-FI smart repeaters, Nextivity Quatra DAS and hybrid designs, validated across all carriers.
The person who has traced a fault through a building at 2am knows things no certification course covers. That field experience is exactly what most audits are missing.
We find these gaps constantly in enterprise audits. One day on site gives you a clear picture of what you actually have versus what you are assuming. Have you verified yours?