I said I think it might be easier said than done on the basis I went through a similar experience when I met my birth parents which is backed up by all the research.
If MM is ever reunited with the McCanns although they are her biological parents they are now strangers too!
That has nothing to do with the McCann's still thinking of Madeleine as a four year old.
Yes they will be strangers, but the McCann's will know she is alive and where she is, the not knowing must be terrible for them.
I watch 'Long Lost Families' and even though some are babies when handed over for adoption, some of the mothers by Birthday cards every year for their child, and wonder if they had a good life, for them they are eaten up with guilt for giving their child up for adoption and the not knowing what happened to their child is a burden they carry for years. When they are reunited they cry and say its as though they have always known each other, and they will have a relationship with the mother, child who they have been reunited with.
Hopefully, if Madeleine has been taken by a couple who have brought her up, Madeleine will still want a relationship with her biological parents.
Also, it needs to be investigated how Madeleine was taken and by whom.