John,
It's also possible to start a fire rubbing two sticks
together, but it isn't as likely to be an accidental thing.
I would tend to doubt any claims about cell phones starting
accidental fires unless there has been some modification
to the phone, or other unusual circumstance. Turning off
cell phones and radios seems like a reasonable precaution
while fueling, I don't have a problem with that. I also
don't understand why anyone else would either. Do I turn off
my two way radio when fueling? Yes, but mainly because of
how it's connected (ignition switch).
If fuel vapor liable to ignite because of RF? Not unless
the RF field is very strong, or the antenna arcs for some
reason. Very likely? Not really. Possible? Sure. So using
a little common sense... what's the problem?
'Doc

PS - Cross posting is a sure way of causing misunderstandings.