The nhancement bonus applies every time you roll damage from a power that originally had the weapon or implement keyword, even if it currently results of an automatic damage effect that no longer requires an attack roll.What about "extra" damage: like the one triggered in Hellish Rebuke or Dire Radiance?
Or "special" extra damage, like Curse damage, Sneak Attack or Hunter's Quarry, especially with feats like Empowering Shadows (When you have concealment from your Shadow Walk, you gain a +1 bonus to damage rolls)?
I think it needs a little clarification in this zone...
So if an enemy starts next to your wizard's flaming sphere, you add the enhancement of your implement to the automatic damage. If an enemy moves away from your swordmage after you hit him with booming blade, he takes your sword's enhancement bonus on his automatic damage.
Some month ago there was a long discussion about this topic until one of the designers stepped in and confirmed that the bonuses (not just enhancement, also weapon focus and similar bonuses) apply to these damage rolls.