I guess my concern is, to lay it out, the difference in definition of "Line of Sight". The rules say you can only target things that you see without "scrying or other effects", but the reasoning it gives is the problem of concentration, not necessarily reach.
A lot of the comments here feel like the assumption is that any evocation must be sourcing from the Wizard in question, but I see no reason to assume that this is true. Harry himself focuses on effects that focus on him and either shield him or radiate out (blasts of fire and air being popular ones), but there are other examples where this isn't true. The rules use an example (page 253, I think?) where someone causes strong winds to rise in the area, but the winds are independent of the wizard (they're near him, but not radiating from or directed towards him), and in fact it's implied that their effect is not limited by LOS to the wizard either - that the effect is an area, obstacles notwithstanding.
Similarly, under the discussion of elements and air vs. earth for calling lightning, it talks about summoning lightning down from the sky to hit a target. The wizard is the source of the magic, but neither the source nor target of the effect.
And the last example I'll throw out is from Storm Front. In Chapter 22, Harry causes
a massive wind gust to form underneath the elevator, forcing it up and crushing the scorpion construct. It could have been framed as a spirit spell just pushing the elevator up, but instead it was framed as wind
- and the source, cause, and effect all happened outside his vision.
I'm just afraid people are getting too attached to "direct vision" as the definition of effect for evocation, because we have multiple examples - in the books and rules - where it isn't the standard used to define "Line of Sight"... And the reasoning written behind the LoS comment doesn't mention vision at all.
So to get back to the thread...
...you just need to point/gesture behind you and you'll (probably) be able to hit them - they could always use a, ah, MIRROR SHOT aspect for a bonus to their defence...
This is exactly my point. Yes, if you're aiming in a mirror to "point and shoot", you're effectively firing a gun, and it'd be appropriate. But am I simply missing the requirement to "aim" in this sense? It may make sense based on the character concept, but from my reading of the rules it isn't appropriate to all Evocation, or even *much* Evocation. The rules say the discipline roll also counts as your attack roll (that they can defend against), but it doesn't say it's literally a ranged attack - and that interpretation is directly contradicted by the discussion slightly further down of, for example, summoning a lightning bolt from the sky. Sure, it's dodgeable, and if not dodged the damage is resistible, but it's not being aimed in the way you're talking. It's being guided, and that's different. Even if my PC were targeting the lightning bolt in a mirror, I wouldn't be able to justify a defensive aspect like that. Now, an "insulated" aspect because they were in a car (rubber tires FTW!) or a "grounded" aspect because they're standing in a puddle of water or clutching a metal fire escape...
Anyway, sorry, rant done.