I'm pretty sure you don't understand the significance of the "inline" in "inline LED." We're talking about an LED that will always light when the camera is powered up because it gets power when the camera itself does, from the same physical wire. It is on if the camera is getting power from the port. You could build a prototype with an LED spliced into a webcam's USB cable if you need to convince yourself that this is possible.
It's not a software hackable thing because of the physical orientation of the LED. This is where the current designs get it wrong by making things too complicated (though they have their reasons).
edit: I'd note that these features we're talking about aren't mutually exclusive
You're missing the "tamper evident" part. A laptop with the LED wired using a microntroller looks externally identical to a laptop with the LED wired inline. But you can always tell whether a cover is over the webcam or not just by looking at it.
A mechanical sliding piece of material without any electrical components at all must be considered simpler (and thus "less engineered") than an LED, mustn't it?
I would be way easier to convince that a piece of plastic is harder to hack than a LED. For instance, there would be no embedded microcontroller to subvert.
Also, USB is a bus, you can't splice an LED into the power line of the USB going to a camera and conclude that when the LED is lit, the camera is recording. There's a lot of other traffic that could be happening beween the host and the device, that doesn't mean the camera is performing any recording. The reverse would of course be true, though (no light = no recording).
> A mechanical sliding piece of material without any electrical components at all must be considered simpler (and thus "less engineered") than an LED, mustn't it?
Looking at my current macbook lid, I don't how how that would physically fit. The camera would need to be recessed further into the lid to accomodate for the door.
> I would be way easier to convince that a piece of plastic is harder to hack than a LED. For instance, there would be no embedded microcontroller to subvert.
I'm inclined to believe that a mechanical sliding door would have a higher failure rate than an LED.
> A mechanical sliding piece of material without any electrical components at all must be considered simpler (and thus "less engineered") than an LED, mustn't it?
Absolutely not. The moving parts vs. no moving parts divide is pretty huge, and an LED is not a complicated thing.
> I would be way easier to convince that a piece of plastic is harder to hack than a LED. For instance, there would be no embedded microcontroller to subvert.
Having the LED in parallel on the power line is impossible to subvert without a soldering iron. I don't know why people are having trouble understanding this bit.
Perhaps to do this properly with a USB camera you'd need to give the camera its own USB controller. My god, who cares? The USB thing was just an example. The point is that you can wire in an LED such that when the camera has power, the LED has power.
> that doesn't mean the camera is performing any recording
The light today doesn't signify "recording," it just signifies that the camera is on.
Well, Ideally I wouldn't want to keep opening and closing the slide up and down. So this is simpler but not nearly that useful. Apple strives to be secure and easy to use. That's why the top dollar for apple products.
It's not a software hackable thing because of the physical orientation of the LED. This is where the current designs get it wrong by making things too complicated (though they have their reasons).
edit: I'd note that these features we're talking about aren't mutually exclusive