glory bound, I'm sure your kids are really good kids as you say; but I have to agree with Dwayne--kids will be kids--even the really good ones. And it would only take a couple of seconds, even for a four-year-old, to pull a chair to the railing for a better look. At four, or even seven, they have no sense of the danger involved in this environment that is completely new to them. And a sudden strong breeze or lurch of the ship could easily cause the unthinkable.
And I would have to take exception with Jim's comment about the doors being difficult to open. Maybe they are on some ships; but on a recent Princess cruise out of Los Angeles, we had just found our cabin and were checking out the balcony, when our neighbors asked if we could get the steward for them. They were checking out their balcony when their 3-year-old, who was inside the cabin, locked them out. The lock is simply a lever that a toddler had no trouble pushing down to lock--and presumably would have no trouble pushing up to unlock.
For peace of mind I would want an oceanview with children that age.