jaclaz, I did read fully what you wrote, as you will see below.
If you can find a protective bag that performs as well or better, for a lower price -- fabulous. Market competition will separate the wheat from the chaff. For now -- and this is the actual point of posting the link to that article, a point that has been ignored in this sidetracking discussion -- a major daily newspaper saw fit to remind its readers (no doubt some of them learning of this concept for the first time) that there is this kind of product out there that they can use. It is not the sort of thing that a user would conceive of automatically, so articles like this one are helpful as springboards for researching one's purchases.
Sorry, but no , you haven't then fully got the technical (please read as "practical") point I was trying to make (besides the "commercial" one of managing to sell something at 5x it's market value).
A cellular phone is BOTH transmitting and receiving.
The "transmitting" part is normally VERY LOW power (otherwise it would fry your brain) in operation and even lower in "stand-by" and cells antenna are VERY "sensitive", but when it cannot reach a cell antenna the intensity of transmission from the phone is raised noticeably (it tries "desperately" to make contact to a cell).
This means that the power consumption (battery drain) will raise noticeably.
A phone whose battery (fully charged) would normally last 24 hours in standby, may be drained in as low as 4 hours (yes, up to x6 factor roughly, of course greatly depending on model and firmware/telecom provider) if isolated from network.
The "need" for a "insulating container" for forensic scopes is of course different from that hinted in the mentioned article (mainly it is to avoid that anything inside the phone is altered and that there is no risk of having it switched off because th ePIN or access password may be not known), but the experience using similar "Faraday bags" devices since years has led to a whole set of "externally powered" containers, using large capacity batteries to guarantee that the power to the phone is maintained for long periods.
So the advertised thingy, besides not being particularly new (and since db are on a logarithmic scale the claimed "leap" between 80 and 100 db is really hard to be trusted at "face value" - and BTW very few "forensic Faraday bags do reach 80 db attenuation):
is of very little practical use, as after a few hours inside a perfectly shielded container the phone will switch itself off because of the battery going to 0.
A "normal" user (which does have his/her own PIN/password) would have a much easier way to isolate the phone by simply switching it off/removing the battery.
Since the "new" bag has no "window" it is not like some of the forensic bags with which the "offline" functions of the phone can be used.
So, the only advantage (provided that the shielding is actually effective) would be that taking the phone off the bag is faster than re-inserting the battery/switching it on when you want/need to use it (a handful of seconds), what I was pointing out is that there is a not-so-little drawback, which is the concrete risk of finding - when you take the phone out of the bag - that the phone has switched itself off and/or that there is no power left in the battery.
With all due respect to the good guys/gals at the Daily Mail, they (as well as a number of other UK and non UK newspapers) also publish articles like this one:
what they "see fit" to make their readers aware of can be of greatly variable nature, and they did not seemingly care to clarify it was a joke/hoax, like - as an example - the Telegraph felt compelled to: