How bout a border on the top part???? Maybe it'll "complete" it.
I'm thinking a red top border would brighten it up a bit.
If you add the border on the top, you may have to add some writing above the school logo to make it more centered since the school name is on the bottom. Maybe even something like "Good luck", etc. that would fit the occasion. But, I don't think it would be absolutely needed - just a suggestion.
Yep... a border for sure.
What about adding some curling ribbon (red, white & black) to the upper corner? Seen it done on some sheet cakes here & looks really cute (Cakery did one for a baby shower cake). That might add some color and coordinate with the flag.
I 2nd the curling ribbon motion.....I think it would look really cute & it would be fast & simple. (Good idea Donnya!)