If that's the semantics you want to be dabbling with then I guess yes, ghosts do really exist for some people as much as colours do really exist for people who are not colour-blind.
I just find it an interesting idea that what is "real" may differ a bit between persons. So when a person say he saw
something, i don't doubt they saw, or think they saw
something, what that
something was is open to wide interpretation. In the "real" reality, however, i have no reason to beleive they exist.
Personally i watch Most Haunted and similar shows purely for comedy value, same as UFO conspiracy "documentaries". Though the last one made me facepalm so hard i had to turn off the TV to avoid brain damage.