I'll come off as an ass, but I'll put it out anyway.
People do come into these kind of rationalizations by taking a wrong idea and beginning from there. They say they "heard something," or that "it felt sooo real." Face it, that hardly proves anything other than what those people say is the truth...in their eyes.
Can ANYONE explain what a ghost is? I mean REALLY. Then, what is a person? what components that a person have somehow interact with reality in a way that produces some sort of incorporeal "image" of whatever.
I already went out on a limb, here, and actually gave a naturalistic explanation, my fault (and a dumb one) was not to provide sauce. Well, here's the sauce:
http://www.bioedonline.org/news/news.cfm?art=2805
http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2006/10/08/MNGNELI3IO1.DTL
You have to at least give some credit to THAT. Now, would it be that there's some glitch in the system, we mammals have some kind of special property that insects don't, or more likely there's just LOTS of electromagnetic fields out there?
EDIT: Technically there would be a glitch in the system. Our system, not reality.