I feel and hope, as you do, except that I would prefer to keep my tree private, to those other than family members ... the latter including cousins through personal aquaintance, paper trails meeting at some crossroads, or through shared DNA. Since Ancestry is offering few privacy differentials during this 'beta' phase, there are but two options available to customers, so ....

I do suspect that not a few people tested here in order to determine their ethnicity, and that is why their trees remain private or undeveloped, and why they do not respond (though, perhaps, they should) to requests for sharing of ancestral information.

There are so many birth-parents who, growing older, have searched for their children, sent out into a world of which they no longer were a part. Parents relinquishing children a hundred years ago lacked the resources which are available to us today. Maybe we should assume the positive: that they would wish for their children to be found and connected (rather than hidden).

We long thought that we had the birth-surname of my adopted grandmother, and I searched for decades to make a connection for her to a likely family. I never would have known to look in the direction that autosomal-DNA has taken us, and believe now that it may be possible, at least, to identify two of her biological grandparents in the forseeable future.