Dusky frustration does on

When a new Dusky Warbler turned up at Gib Point on Monday afternoon it seemed like a chance of another photo? showing well early Tuesday by the time I got there needless to say it was the most elusive little blighter you could hope for so some rubbish records BUT -- a Dusky Warbler had been at Gib in the East dunes from the 14th to the 17th when it was trapped -- not seen again after trapping so a bird that appeared 1.216kms away by Tennyson's Sands on the 19th would be assumed as a new bird; indeed views seemed to confirm that it was unringed and in 90% of cases it would have gone down as different but as can be seen here it was in fact the same bird; how many times does this occur with rare birds and clearly with much less rare species like Yellow-browed warbler? just how much over counting does go on?