The link contains an extended quote from Sagan's "A Demon Haunted World"1. It is a good analogy on how to deal with claims… not just claims of paranormal activity, but any time anybody forwards a claim that they want you to believe.
The short version is simply "Show me. Prove your claim". If the claim is true, and if the person is being honest with themselves and with you, they won't have a problem in at least trying to meet the burden of proof. If, on the other hand, they shy away, or make various excuses, then there is cause to think that they are not being completely honest with you.






