I am in the process of selling my MacBook Pro and the buyer if requesting the serial number to "verify warranty info." The computer is registered to me and I did buy it directly from the Apple Online Store so there is proof of purchase right there on the site. I guess I just want to cover myself with all of the fraud that happens nowadays. It seems like it wouldn't be an issue, but you never know these days. The person did write with good english contrary to the very obvious Craigslist scammers.