[quote=@MrDidact]
[@Asura] As far as I can tell, kinslaying is only a taboo if it involves close family (up to and including first cousins) and anyone who bears the same name as you. If you're second cousins and further without the name however, it seems to be open season. Robert killed Rhaegar and they were second cousins. 

So if any of the bastards killed each other they would probably be considered kinslayers but I think the Ironborn probably have a more relaxed view of it, or at least Euron's son definitely would. 
[/quote]

Damned crow.