One book said that the opposite corners should match/be symetrical for balance -
ABAB
BABA
ABAB
BABA
Or
ABABA
BABAB
ABABA
BABAB
ABABA
If all the blocks are the same, it really doesn't matter then.
That's one thing that kind of (okay, a lot) bothers me on some of the Quilts for Kids. I would feel so much more 'at ease' if they had one more row!