Yes there can be many reasons a Spirit will stay behind, with the most common being either not realising they are dead until their 'window' has closed, or the main one which is fear. The fear being the product of the Religious notion that we are all judged and will 'burn in hell', which is not at all true. As for saying some will `never` pass on, that is incorrect as there are people who can take them, and there are also occasionally special windows opened for them.
Regarding your belief that nobody can can do this without physically being there is simply ignorant of the process which is fair enough if you have no experience or education in the field. These non physical elements cannot be dealt with via physical means, it just doesn't work that way. There are thousands of people who have been helped remotely and have had noticeable and positive change, many of these people not even knowing they were helped, but the change being observed and reported by those who requested the work to be done.
kskattebo, on Nov 7 2010, 11:05 PM, said:
There are many reasons a spirit may stay behind. And no matter what anyone thinks some never will pass on. I do not believe anyone can rid anything of a spirit just mentally without even being there, that to me falls under the same realm of pshycics of yester year that were all provin as frauds. Beware of "free gifts"