I had a lady on Ancestry contact me, on her tree was the same family as I had, on paper we shared 4th gt grandparents. Her gt grandmother never married but had children with a man she lived with.
She had her DNA on Ancestry, I haven't but told her I was on GEDmatch with 2 others who have linked on GEDmatch for this family.
She's now having to take out the family, her gt grandfather isn't who the family said fathered gt grandmother's children.
None of us on the one to one had any links even down to 1cM.

On GEDmatch I have proved my paper trail for both paternal and maternal lines so I am happy with being on there as it's produced 8 known hits from other DNA companies to my own. I have several outstanding that I'm trying to find the family links.
I have had more respond to me than haven't.