Ok. Here's how I see the whole thing:
The Haunted Mansion opened to guests in 1969.
Hitchhiking was really how the "young " generation got places in the 60's/70's. Seriously, some kids from the midwest hitchhiked to SF.
So - those hitchhiking ghosts at the end of the HM, its actually more a dated sight gag than a commentary on who wants to leave.
This could prove fun... what counts as a haunt now? Does whatever is behind the door, stretching it out, count?
Our revels now are ended. These our actors, As I foretold you, were all spirits and Are melted into air, into thin air: And, like the baseless fabric of this vision, The cloud-capp'd towers, the gorgeous palaces, The solemn temples, the great globe itself, Yea, all which it inherit, shall dissolve And, like this insubstantial pageant faded, Leave not a rack behind. We are such stuff As dreams are made on, and our little life Is rounded with a sleep. mycroft16 on Twitter