I am aware this thread was started in 2009, but it could be useful to others who look up this story; it IS an urban myth.
My mum told me this story when I was in Primary School (age 6-10). I'm now 27 years of age.
Her version of the story that it was Bluewater Shopping Centre in Kent or Lakeside Shopping Centre in Essex (I can't remember which, but we live close enough to visit both) - and that the kidnappers got away with the child, nothing about the woman being at the checkout or straps "cut".
This clearly is an urban myth, despite others before me saying it was; think about it, if this was told to any of you in 2009 and it supposedly happened 20 odd years ago and has happened again without the most recent incident being in the news; then that's more than likely it's a urban myth.
Not only that, but I now realise the story my mum told; how could the story (of shaving the child's head or dying the child's hair colour, putting the child in opposite gender clothes) be told and the kidnappers "got away". How would any one know those details of what actually happened and got away with the child without telling someone how they did it?
This has been one of my mums fears that someone would take me or my sister while we were out. And of course, it frightens me even now (I have two young girls now; thank goodness for buggie-boards!?)
A few years ago I visited Bluewater for a job interview and I noticed at the bus stops "Missing People" posters; not sure if they ALL went missing FROM Bluewater Shopping Centre or the general area, but a lot of them appeared to be children and at least ONE of them was last seen at Bluewater Shopping Centre, no details of how the child went missing (I.e kidnappers, toilets, change of clothes) - I can't remember if this particular it was a girl or a boy, or how old. I think one of the missing posters was of a 12 year old blonde girl.