At least one of adults will be sat with the children, although it could be over an isle. In my experience it's depends on how busy the plane is. I've often been allocated the row behind, or in one instance 8 rows ahead! No difference between ET and CE, except to say in CE, most people try and book seats as close to the front as possible and many are status holders so do it in advance, which often leads to seats at the back of CE being assigned for whoever is left over, thus you generally sit together at that point.

Long story short, you'll probably be ok, but it depends on if you want a guarantee that both parents will be sat with the children, then prebook. Since making Bronze and subsequently silver, it's never a problem anymore.

Personally, I'd risk it, but up to you.