There is another risk to phones - it won't prove fatal, but it can do a lot of damage. That is the presence of DEET in some of the more powerful insect repellants, especially those intended for use in malarial areas.
As a birdwatcher, I have been aware for many years of the damage that DEET can inflict, particularly on plastics, varnishes and the optical coatings on lenses. You end up with the stuff on the palms of your hands as you apply it to your exposed skin, and unless you then wash your hands very thoroughly (thus removing the repellant from your hands) you end up applying it to anything else you touch. Over the years, I have wrecked 2 wristwatches, 2 pairs of spectacles, and the rubber armouring on a pair of binoculars. Friends using spray repellants have also removed the chromatic coatings from binocular and telescope lenses.
Logically, phones must be at risk of exactly the same damage, and it will become more prevalent as mobile coverage is extended in tropical areas. As I've been typing this, I wondered why none of my phones had fallen victim to DEET, and the answer is simple - the phone signal hasn't been there, so my phone has remained in my pocket, in the bottom of my rucksack, or even in the bottom of my suitcase. But this signal-free situation is changing rapidly in many parts of the world, so remember that mobile phones and insect repellants may not mix well.
