I think it would be just about impossible to answer your question with a simple yes or no. There are too many factors involved to make such a hypothesis. There are some observations we can make that would help lead to a conclusion or at least lean in a certain direction.
1. Children have a much more vivid imagination. Linking real events and fictional events is a simple process in the mind of a child. As we age reality kicks us in the backside and we loose that ability or at least put it out of our mind.
2. Being open to your imagination can be argued as a portal to paranormal activity. If one were to consider being open to that kind of thought as a conduit to spirits then the paranormal world would use that conduit to seek the living.
3. Children are more able to accept changes in life and allow things that would be unexplained just pass as a new experience. Adults having already determined what they see as reality would find it very hard to accept new forms of input.
4. Children are easily manipulated. This is a problem since there are so many out there that would like to prove that paranormal world is real. They take the offensive and will use a child as a pawn to make a false event of paranormal activities. They are not willing to wait for these events to happen on their own and cause more problems in the long run.
5. Children's imagination can be the downfall to a good witness of these activities. If a child does report something it could very well be a conjuring of a wild television show mixed with some real life event and point to the paranormal but in fact have nothing to do with it.
I honestly don't know if children are a good conduit to the otherside but hopefully some of this information is helpful.