I've gone the 'big buck' solution and am converting one of my LiPosafes into a charging box. The case cost 157CHF and the conversion stands at around 100CHF. I chose the one without any divisions inside and can connect both channels from a charger. My intention is to put the fire suppression granules inside to separate the batteries. If one of them lets rip, I expect its partner to go, too or at least to be a write-off.
As far as the LiPo bags are concerned, I've decided to have a bag for each of my 5000mAh+ 6S batteries (12 in total). After watching the video of a fully charged battery going south, I'm sure that any in the same bag would also be damaged or not to be trusted in future. Each one costs 130CHF here! I'm also trying to break the habit of carrying them to the field in a rucksack. I suppose that an ordinary 'environmentally friendly' shopping bag would help to keep my nosy neighbours happy