I manage a kit with an unknown grandfather, but they are not really interested in pursuing any relationships on that side. A close match came up and I built a tree, leading me to believe the Match's father or one of her maternal uncles is the Unknown grandfather. I don't know how knowledgeable this match is about cM and matches, but it will probably be a shock to them when they figure it out that her or one of her cousins has a half-sibling. At this point I'm just sitting back and waiting to see if anyone reaches out or if any other matches pop up.
The reason folks keep others from knowing the reality of their birth parents is because a lot of shame about the specific situation is involved. And the ones hiding everything are looking out for themselves. My family has a lot of unfortunateness in it, but (for the most part anyway) we face it head on. Even if it's of the "Unfortunate events occurred but we got you out of it - a happy thing!" scenario.
