NotBadConsidering - "Anyone can just click “report”.
Only logged-in, registered users can use the "Report Button" on posts. However, Mumsnet invites absolutely anyone to email them to Report posts and those reports are, apparently, treated in exactly the same way as complaints using the "Report Button".
ProdigalKittensReturn - "Not allowed to signpost users to the competition?"
Don't know if you were being rhetorical there so apologies if you were! That is standard for most forums. Even Facebook Groups that are free, non-commercial, etc. often have a Rule about not posting links to alternative sites.
Posting links and spamming
"We have no problem with people posting the odd link to other sites/blogs that other posters might find useful or interesting. But we'll delete anyone's attempts to spam the boards with links, as a way of promoting their own product, services, survey or e-petition, as it annoys our members."
from www.mumsnet.com/info/netiquette
Datun - glad you posted about the very similar username! I was fooled by it!