Well, I only just recently found out that this was going on with the Youtube and Google Plus connection, because on my actual Youtube account, all of my account activity is hidden. People can't see the videos that I have liked, favorited, or commented on. Then I find out that the Google Plus account that is linked to my youtube account is spilling ALL of that information, and more, anyway. And there's nothing that I can do about it. You are correct. Google Plus is another way to find someone easily, and the fact that they have all of your Youtube activity on display on there makes it even easier for people to gather info on you.