I prefer to take a stand here when I have a set, rather than a straight, because i'll at least have a chance of improving in the next two cards.

Another thought... you already raised, why wouldn't CO just call the raise and see the next card?

Protecting, or has the flush?

I don't know of too many people here with just A[img]/images/graemlins/heart.gif[/img] that would re-raise on the flop.