That's just my general musings on the situation though, not a reply to anybody here.
kickassangel I think what you say is right and in our case there's no way they could prove they had a significant relationship with DS.
The didn't see much of him as a baby, never once looked after him alone, he never spent a night with them or even an hour alone while we went shopping. When he was a newborn they lived at the other end of the country and by the time they moved back to the town we live in, the relationship with them had soured so badly that we put our house on the market to put some distance between us.
He hasn't seen them since he was nineteen months old and even at that point he had no idea who they were. He could recognise other family members and his face would light up when he saw them, but PILs might as well have been random strangers come in off the street to him.
Plus, DH and I are still married and have made a joint decision to go no-contact with DS, so that would also work against them I think/hope.
So they have never had a significant relationship with him in the way that other relatives have. DH's sister regularly sees DS and babysits him, she would have more right to go to court in my opinion.
But it's always a concern and a worry. PILs seem to have a knack of getting the right people to feel sorry for them and take up their cause.