[jimktrains2]

Will such a system handle a sudden demand nearing the maximum capacity of its terrestrial counterpart? That's really the crux of the issue: in an emergency public networks can be overwhelmed.

Many county government agencies don't work with hams anymore because they have sat links and other communication available to them. I'm sure as technology progresses and it becomes feasible and affordable to give individual first responders satcom abilities, but I'm not sure that every person with a cell phone will be able to stabily access satcom in an emergency for a while yet.