Who decides first, straddler or poster?

[GuyOnTilt]

I would say that the straddle has to post first, but I really don't know. I doubt it's in a rulebook, but thinking about it practically, if I were the CO I could technically wait till the dealer had pitched to the first few players before putting out my blind and declaring my intention of posting from the CO, at which point UTG would no longer have the option to straddle. Pretty much that alone is what makes me think UTG should have to declare first if there's an issue.

GoT