Actually, the example in my mind was a bit different: "Elegantly invisible", I call it. Let me give a couple of examples.

In Europe, in some cities you see huge planters with blooming flowers. They are well looked after and a bliss to be around them. Look from above, they are strategically placed bollards. Even a tank can't pass through them. Smaller installations are made around banks for example. These "small", ordinary looking planters weigh a couple of tons, plus they're firmly planted to the ground. They are essentially fortified walls, but they don't distract you, and enhance the environment in a way, too.

In Amsterdam Central Station, there is a big locker room, which is invisible if you don't know, but very evident when you follow the signs.

My proposition was similar. A section under battery status menu: No Apps Preventing Sleep. Simple. Invisible, unobtrusive, but bright as day when you know where to look.

I don't like the design you gave examples for. I don't like things which I can't find, and only see if the app seems to be in the mood for it. My proposition is a bit more nuanced. You know where it is, you know where to look, but it's not an eye sore or a distraction.