I have a friend who has the most intense everyday ab training program I have ever seen.
When he puts on bodyfat, it goes to his upper and lower body, and his abs are always cut.
It seems to me that training should have a lot to do with cuts. I am pretty ripped and vascular in my upper body, no matter what my diet is like, and I don't think it would look that way if I didn't train.
My abs are a different story, which would be explained by the fact that I don't train them intensely at all.
If you take a look at most guys into bbing, they have visible abs at all times, yet they are not always in a low carb/high cardio phase.
Training has a lot to do with it!