Well, here's the cheat - so long as a reasonable case can be made for an explanation (as is the case with both 2 and 3/4 here) then the best answer is th eone that works best for play, which is often going to be #2.
My litmus test is this: do we imagine that, if Harry were to hand the item over to someone else, it would continue to function? I generally answer "no", partly because I think there's a component of being a wizard to make them go, and partly because if he _could_ do that, and in all this time he hasn't given Murphy _something_, then he's kind of a tool.
Now, part of the power of #2 is that it's very, very vague. Does the item need time in the lab, tunig it up? Does it need to stay within the wizards aura? Does it need to be occaisionally dipped in puppy blood? On one level, this is purely color: since we're talking maintenence that has to be done occaisionally, it's easy to just assume the wizard does whatever he needs during downtime. Sometimes these can be plot seeds (Your usual source of puppy blood isn't answering calls, and wasnt' that fire you read about near his shop?) but the last thing I want is to turn every possible magic gimmick into a bookeeping extravaganza.
That's a strong case for #2 and #3, but #3 has it's own problems. Most of the abusive scenarios that i can immediately conceive of for magic items are at least moderately curtailed by "It's hard to make something that works without you keeping an eye on it." This won't stop every abuse, and frankly I don't want to - coming up with creative uses of magic is half the fun.
So ultimately, there are three goals:
* Be consistent with the books
* Minimize bookeeping
* Cut down egregious abuses
* Makes for a good story/game
And those are the goals that lead to that sort of breakdown.
Now, here's the other really dangerous part. Magic in the books has its own rough sort of physics, and in an ideal universe, we could express those principals so clearly that the capabilities of magic are as clear as the extent of physics, and it will be as obvious that a threshold stops power as it is that you can't jump to the moon. That's not entirely doable, and it creates a dangerous situation where we have an incomplete set of rules.
Figure day to day physics has a lot of implicit checks on crazy things we might want to do, and we naturally understand them. Magic is the same way, and when presented with a magical proposition that takes advantage of the rules we have and has no apparent check, that's when we need to start thinking like Jim. See, for all the magic, the Dresdenverse _hasn't_ been split in half by some wizard's perpetual motion machine or magic eating tribbles or god know what else. Some of that is because if you do something like that, someone will probably punch you in the face, but mostly it's because the world of magic is robust and dynamic and because Jim can make stuff up that fits within the _less_ strict logic of the setting.
Which brings us back to sunrise. Really, do you know what spells are disrupted by sunrise? The really inconvenient ones. Oh, if you've got a black belt in Dresden Logic, as Jim does, you can easily enough justify it according to some nuance or detail, but the reality is that it's a decision that mostly hinges on what makes a good story, or in our case, game.
And that's why you'll find some waffling. If we lay down specific details without the whole supporting web of logic behind it, we're begging for trouble, and honestly, I get enough trouble from the shield bracelet that I don't need to hunt for more.
I realize that's not entirely satisfying because, frankly, it's kind of cool to think "Ok, if magic can get energy from kinetic energy, I'm going to hook up a feed to the interstate and get a little energy from each car passing, and have a limitless supply of whupass." But there are at least 3 reasons for that not to work, possibly many many more, and until we give the tools to make those reasons transparent (and more specifically, the tools to deal with it in a better way than just saying "no"), we're only telling half the story, and doing a grave disservice to anyone looking to play.
-Rob D.
-Rob D.
