I thought the same thing about Jorah finding the ring, until the establishing shot showing the big ring of kicked up earth around a pristine 6' circle, something that would be pretty visible from a ways away. Danny dropped the ring directly in the center.

If you want a better example of "Oh, how the hell did they spot that!" you could look at Lord of the Rings, where "not idly do the leaves of Lórien fall." At least Danny's ring was in the center of a noticeable patch of ground, and not a muddy patch of grass, to be immediately trampled by a bunch of heavy muddy feet.

Also, is it actually implied that this is Melisandre's nightly ritual to do this? I thought they'd previously established that she doesn't need sleep, that the Lord of Light provided everything her body needed (except the occasional dick, I guess).

Discussing it with some other fans, we wondered if this wasn't instead her way of being emo, taking off her necklace as a way to die, because it seems like she's going through a pretty serious crisis of faith. I don't think she'll actually die, since you point out that she has go do some resurrecting before she kicks the bucket, but it was an interesting theory.

She looked so sad just before taking it off. She can't do that every night...