I have had some experience in this field, having been involved in Spiritualism many years ago, to the extent to taking mediumship training. I have to say that in over four years of attenting Spiritualist services, seances and readings, I never saw or heard anything that couldn't be explained.
Totake just one example: At one service, when a medium was on the stage , she called out "I'm getting the name 'joe', does anybody know a Joe?" She gave no more details than a name - it could have been the name of anybody - or anything.
A woman promptly shot up her hand: "Yes, that's my new grandson!", and the medium gave her a message to the effect that he would be a remarkable child (without giving any details).
After, when the woman was outside talking to friends about it, I heard her exclaiming "Isn't it amazing how she knew my grandson's name!" She'd entirely forgotten that she'd given that information to the medium!
Time and time again, I observed the same thing - people heard what they wanted to hear, and remembered what they wanted to remember. I suspect that if some of the people on here had taped these 'accurate' psychic messages, they'd find they weren't as accurate they remembered.
I have to emphasise that I didn't start out as a sceptic, not at all - like that bloke on the X-Files, I wanted to believe. But I couldn't believe without proof, and I found none.
Finally, as grandtante's granny said, if the dead do live on, they'd surely have better things to do than hang around mediums passing on vague messages.