OP I'm so sorry you were upset by a journalist PMing you :(
And it was definitely out of order - because it would appear (as stated above - I haven't actually checked the source!), that anyone using the PM system is instructed that journalists shouldn't use it for this purpose.
However, it is probably worth bearing in mind that not all journalists are 'hacks'. The majority don't work for the gutter press. A huge number work for Junior, Mother & Baby, Caravanners Weekly etc, writing informative, useful and inspiring features...the type of feature that most of us read (OK, maybe not Caravanners Weekly), and extract useful advice from. And this particular journalist may have been trying to research a feature to help other people who found themselves in a similar situation to the OP.
And it's not really lazy journalism. She may have spent literally hours trawling forums to find someone with a relevent and interesting story to highlight her feature. All she was looking for was the contact - she then contacted the OP to see if she was willing to tell her story. And in that position, many people are actually grateful for this opportunity (for various reasons). Hopefully, when the OP said she didn't want to talk to her, she apologised for intruding and backed off?
I think most journalists do this - it's unreasonable to expect a single person to actually already know someone who has (eg) been in a plane crash, dated Annie Lennox, suffered horrific food poisoning, given birth to triplets, and everything/anything else they might be asked to write about, so they use various ways to find them.
MN charges £30 to post a request. The journalist in question might have been a staffer, in which case she'd probably struggle to pursuade her publication to pay this, or she might have been freelance, in which case she may have been paid as little as £150 for the feature - £30 to MN, phone calls to the OP if she'd been interested, other phone calls for research, maybe two to three days of her time on the Google and the phone, and writing the feature...she'd be better signing on!! If MN didn't charge, the journalist in question would undoubtedly simply have posted a request for interested people, because that would be a quicker route for her. And a more comfortable one - she probably had to steel herself and hold her breath to contact the OP about a very sensitive subject - she may not actually be a thick-skinned old hack, but a perfectly normal young woman, doing a job that can sometimes be challenging. Just like most people.
Also, it isn't really like overhearing something on a bus because simply by writing on this forum you've agreed that MN pretty much own your words and have the right to reprint them. If MN want to right a book, for example, they can use all your comments and posts as they wish. Without contacting you to ask your permission (because you've already given it) or sending you a proof to see before it goes to print. If you talk quietly on a bus, you risk a handful of earwiggers overhearing - if you post on hear you deliberately make your words public to potentially millions of people, as well as giving MN the right to re-use them at will. Which is basically the reminder the OP is giving :)
Still sorry you were upset OP, just clarifying the journalist's position.