Those who say that mobiles are not a problem are correct. To date there has been no confirmed report that a mobile telephone has ever effected an aircraft system beyond some audio noise. Often reports of mobile telephones effecting systems are coincidental with other faults.
Mobiles CANNOT cause a spark to ignite fuel during refueling. Their EIRP (radiated power) is way way way too low. Even if a spark was caused, the chance of THAT particular spark causing an ignition are miniscule. I have seen sparks jumping around the pipe network of fuel trucks and fuel rigs during pumping with no effect.
Mobile batteries are unlikely to cause a spark as they are typicallo low voltage batteries
Hand held radios on the tarmac radiate tens of times more power
Diesel tugs on the tarmac with 12 volt electrical systems and pieces of metal that dangle on the ground pose a far higher risk.
The reality is that because airlines and wowsers who don't understand radio think mobile telephones must be bad they use all the above excuses to ban them rather than the truth - people are scaired of what they don't understand.
FACT: It is perfectly legal to install a mobile telephone in an australian registered aircraft.