On the subject of false decodes, Jim Lill is working up a continually updated whitelist database which may live on wsprdaemon.org.  You can imagine that one of the many difficulties is allowing for valid single spot reports and as a result  the benefits of removing the few hundred spots per day may be outweighed by the few good single spots which are flushed.  Watch for Jim's reports.

It's a complex problem because while false decodes are usually bad call signs, good calls also appear in bad decodes making it even harder to validate the spot. My whitelist scheme, which is not online yet, produces some audit files which I am reviewing several times a day to check the accuracy of the detector. A challenge!

-Jim