Well, it could be that Sharon will wait until Gaza becomes officially Palestine, and Palestine gets recognized as a nation. Then "gunners" firing across the border is an "act of war" at which point Israel can respond by invading and taking out the bad guys under all known international treaties. And once and for all end this thing.
That's years, likely decades off. Sharon has indicated that actions will be harsher than in the past. I'm skeptical, there's no upside to retaking that land.