Originally Posted by MNManInKen

Ah, this old chestnut. There is no doubt that powered devices, especially those that are designed to be transmitters, generate interference potential. And what most people don't seem to understand (a little bit of knowledge is always a dangerous thing) is that the main issue is not one of individual devices, but of dozens of people powering up their phones at the same time, in a confined space. It's this combined and concurrent use that can cause (and indeed has caused) significant interference profiles. When powered up, the phone will also start broadcasting at fairly high energy levels in an attempt to set up the radio link with a base station. Doing this from inside a Faraday cage will only exacerbate the problem...

There are well documented cases of this causing problems in planes, with for instance compass equipment and GPS receivers - some of this is in the public domain. Obviously, technology evolves and in fact modern telecom protocols are less prone to generate intrusive interference than older ones, but it remains a source of potential problems.

That is why authorities impose rules on the use, this is perfectly reasonable and rational and people should stick to them. Amazing how many idiots think that their ignorance is in fact evidence of absence of a problem.

Would it be better if rules worldwide were more aligned and consistent? Yes. But that is an argument for tidying them up, not for flouting them.