Thanks Bertrand, you've made your point perhaps.
I think the group has put forward a suggested rename to "Emergency Preparedness" to help people realise what this section is about and post appropriate discussions, so hopefully that will help.
However - the term "preppers" does cover a range of activity, from "spare chocolate bar in bag" to "a week of food" to "a secret bunker in the Himalayas" so it's not an incorrect label as such, more traditionally stereotyped to one end of the spectrum - and there'll always be some parent who wants three extra generators and a month's worth of food as opposed to the one trying to keep their car keys in one findable place.
Also (and I'm playing devils advocate here because I really, truly hate the idea of guns and it sends chills up my spine how normal it is for some) - there will be parents out there posting who do have guns, and do want to talk about them as part of their parenting experiences. They'll see it as part of their parenting duties. And while I don't think that Mumsnet is the place to chat about it whatsoever, anyone can post any topic at any time - such is the nature of the Internet.
I do hope it becomes more apparent what is and isn't appropriate, welcomed discussion and I wouldn't mind a bit of rock solid guidance from Mumsnet on this either ... But sometimes it takes a while for a board to find its feet.
Meanwhile this has still been an informative post, if a bit chilling. I genuinely hadn't clocked that there would be regular people like chilled who keep a gun in their handbag, and as such it's another thing I've realised I take for granted about Britain and hope it doesn't change.