Some people are just sloppy about protecting information on-line. I am going to give them the benefit of the doubt that they did not mean harm but were definitely careless and reckless. One thing Ancestry users need to pay attention to is Notes vs. Comments. Notes can only be seen by the owner of the tree and anyone with edit capabilities. Comments can be seen by anyone unless the comment is for a living person. But even then there are settings where this restriction can be relaxed. So if you add a comment about a living grandchild but it is attached to someone that is deceased it will be visible.

One more thing... the comments go to the "owner" of the account and it is a good way to inform them of the information that is in question. I am not sure who can see the comments, I can on some tree's, yet I am invited to them, others do not display the comments, even on photographs.