It always gives me a great deal of peace of mind when I hear Dan talking. People like that (and he confirmed so in one of his videos) sell at the moment they have doubts about the project. They are not here staring blindly, hoping for a better price, they are here because they believe - until they stop believing.
Anyway, yes, thanks for notifying me of his video, it was very uplifting - again :-)
In some way they are indicators of trends and when they sell, it doesn't mean disaster but it is worth having a closer look.