If you are always asking yourself whether an OP is genuine or not, it becomes a bit wearying and makes you hesitant to contribute.
Is that not the deal with the people who create forums: their job is to keep on top of abusive posts and trolling and in return the users create free, fresh content for them?
I don't know if Mumsnet had been understaffed or what this last year, but it feels like the troll get far too much opportunity.
If understaffing is the issue, it might also explain the lack of proper communication when suspending and having posters.
Why would you keep manpower low though? The company makes a profit so can afford more employees. Could it be related to the theory over on redditt that the company is preparing for sale, or even just looking for a large investment so needs to appear as profitable and with as much scope for growth as possible?