In the series Pushing Daisies, Charlotte "Chuck" Charles is born to Charles Charles and Lily Charles. However, it is explained that this was an illicit affair between the two, as Charles Charles was engaged to Lily's sister, Vivian. Considering that there was no familial relationship (or presuming?) between the three--and none ever married--is it mere coincidence that all three of them had the same surname?
It seems unlikely they would have changed their name to Charles upon adopting Charlotte, and this suspicion is further validated by the last episode "Kerplunk" when the Darling Mermaid Darlings are addressed by their long-time rival as 'the Charles Sisters'.
Is this writing oversight, coincidence, or is there any other explanation?