I played an unlisted video and it started appearing when I searched for it. I do not want this and I hope that this is only because I have played it before and does not appear to others.
Hey… unlisted on YouTube means that the video is not listed on YouTube itself but it can happen that other search engines pick it up. Actually there is no sign from YouTube to indicate whether a video is unlisted or not. If you don’t want this to happen it would be better to set your videos to “private” on YT. In this case you can send me a link to your video as PM and I have a look if and how it was indexed.