They shouldn't. That's meta-gaming through exploitation of knowledge of the rule system. It's very close to cheating.
Being included in films doesn't necessarily mean that it's realistic. It shows more about what we wish was realistic, and what we find to be inspiring moments or stories that resonate in us.
In other words, sometimes it's not about what is reality, but what we wish was reality.
Well, first, low level parties DON'T have access to that magic, and there's a gih resource cost even for high level parties which DO.
Second, if you argue "The PCs have off-screen magic which heals them all.", then you ask, "Why doesn't anyone else?" "Can the PCs single-handedly heal an army?" "If it's something special about just the PCs, why do NPCs travelling with them also heal overnight?"
Further, the rules hold whether or not "magic" is being used, or not. A Warlord heals as well as a Cleric, and there's no such thing as an injury "only magic can cure".
Again, the issue doesn't start causing fun-ruining SOD issues when you're just adventuring. It causes issues when the PCs interact with the world outside the dungeon and you try to reconcile "how everything works for us" vs. "how everything works for everyone else".
If your players never interact with NPCs beyond, in effect, clicking the "Accept Quest" button, then, it's unlikely to ever bother you and you likely don't understand what all the fuss is about. If your players try to pretend they don't know who is a "PC" and who is an "NPC", and treat everyone equally, the difference in how the rules work quickly becomes glaring, and not just in terms of healing. The "shallowness" of NPCs who are supposed to only last one combat becomes very evident if they're long-time companions of the party.
See, I think it's the opposite of cheating.The characters live in the world, they know how the world works.
If a "plot element" makes no sense under the rules, I expect the *characters* to be curious as to what's really going on. My personal rule on stretching the bounds is that an event does not need to be PROBABLE, but it ought to be POSSIBLE. An Eladrin shouldn't be jailed in a cell with a view of the outside world, and if he's not escaping, the characters ought to wonder why -- is it a warded cell, or does he not WANT to escape, for some reason? The thing which must not happen is that someone ask the Eladrin why he hasn't telported out, he replies, "Oh, I forgot I can do that." or "The plot required me not to."
We're not talking about what the characters know. The meta-game information you're talking about is things the characters don't know, though the players might. When you bring up things in the rules and try to use them to invalidate events in the world, that is actually relying on the rule system, something the characters as a rule, do not know.
Sorry, but this particular example isn't a good representation of the problem, which may come up with regards to meta-gaming such as has been the issue here. Eladrin being able to teleport isn't something that would require rules knowledge to know.
I've got to go now, so I can't give a better example at the moment, but that's why I don't consider yours to be a problem. It's not a rules issue.
Putting it another way: If someone told you, I dunno, Hulk Hogan, in his prime, was killed when someone through a balled-up sock at him, would you be at least a LITTLE suspicious? To a person who lives in a world which runs by D&D rules, a powerful individual dying from a trivial damage source is just as odd.
Sure but reality is way more extreme than people think, and second winds are familiar to about every high-school or better athlete in existance they describe it as there fatigue going away and similar things the doctors call it epinephrine released in response to the pain associated with fatigue. (it tells the body to pump/process the blood better among other things which really will fix the chemical problems of fatigue its not just pain suppression)
Human Body: Sensation - Pain : Discovery Channel
My halfling buddy calls using a second wind as his luck turning around... However you skin it I think its quite fun.
I disagree. The characters may not know "Sir Fred is a 10th level fighter with 100 hit points, and a fall from a horse can do 2d6 at most", but they DO know just how tough someone with Sir Fred's experience is, and that he has survived far worse falls with no serious effect.
Putting it another way: If someone told you, I dunno, Hulk Hogan, in his prime, was killed when someone through a balled-up sock at him, would you be at least a LITTLE suspicious?
To a person who lives in a world which runs by D&D rules, a powerful individual dying from a trivial damage source is just as odd.
It's an example of the larger problem dicussed here, that of shaping the world so that it makes sense according to the rules.
These things stick in the back of my mind and keep me from enjoying 4e as much as I should.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.