I always wondered if the Beatles autographs my British pen pal Joan sent were real. Joan said in a letter dated 2/8/64 that she'd gone to the airport and gotten autographs. The Beatles actually were at the London airport on 2/5 (coming back from Paris) and 2/7 (going to the U.S.). It's possible she was there, but the signatures looked too neat to have been scrawled in an airport with hundreds of screaming fans. It did look a bit like their handwriting, but also a bit like Joan's handwriting.
I recently found the autograph book and decided to get it checked out, as all four Beatles signatures on one page is now worth quite a bit (and probably more if anyone else dies). I found a service that evaluates autographs based on a scan, for $7. They have experience with Beatles. To get a certificate of authenticity would cost $70 + certified postage, so I just did the scan. The result:
**Please note this based upon a scan. The only way to truly examine and authenticate an autograph is to physically examine the signature, the ink and the item that has been signed.
I'm impressed that they didn't say it looked real, thus encouraging me to pay more to send it in and get the certificate.
As contrast, here's an authentic (according to the Web) set of Beatles autographs:
The little square of sheet that Paul allegedly slept on did come with a letter of authenticity; at least, he was in the hotel at that time.