Carryover from 2E, with a side of future proofing
Looking through the rest of the Exalted 3E books (and I think I have all of them up til now) the only other mention I found of scrying was in Arms of the Chosen where the "witch-queen of the waste" was scrying in a "frozen scrying pool."
However, if you look back into 2E, you can find things like Coin of Distant Vision a Terrestrial Circle spell that lets you conjure a black ceramic coin, leave it wherever you'd like, and then transfer your senses to that coin whenever you'd like. (ref: White Treatise, page 40) It doesn't use the word scrying, but...it's remote viewing, which is what RPG Scrying is.
From the Black Treatise, there's also the Iron Circle spell Dusk Eyes which lets you peek from the Underworld into Creation and explicitly calls out that wards against Scrying block it from functioning. (B Treatise, p27)
So if either of these spells were brought to 3E, they would be blocked by these anti-scrying effects.
There are also Artifacts such as Dragonfly's Ranging Eye, which can allow scrying at up to a mile distant
Also, Sidereals do not have a splatbook out yet for 3E, but in 2nd Edition they were very capable of Scrying. The act of Searching the Loom of Fate to find someone or something is referred to as a form of scrying (MoEP - Sidereals p. 62)
So given the existence of things that could scry in 2nd Edition, it seems to me that future-proofing your content to cover for these things is prudent. Many of the Charms that jam scrying were also in 2E and you wouldn't want all your earlier splats to have no defenses against abilities you mean to give your latter splats.
Sorcerous Workings
Comparing 2E to 3E, a number of spells have been loosely translated into a Sorcerous Working 'example.'
For example: "Ward a chamber against scrying, teleportation, or intrusion by a particular type of spirit." as an Ambition 2 Terrestrial Circle working is, well...it's the 2E spell Private Plaza of Downcast Eyes (White Treatise, p55) in far fewer words.
So it's not unreasonable that a player could come up with sorcerous workings that allow them to Scry. After all,
Create a rift between two realms of existence that allows communication, possession, or similar forms of limited interaction, but not actual transportation.
is an example of an Ambition 3 Terrestrial Working. If an Ambition 3 can create "limited interaction" with other realms of existence, it's entirely reasonable that a same or lower Ambition Working could create "limited interaction" with a different location in the same realm of existence.
One possible example in 3E
The spell Spoke the Wooden Face (DB, What Fire has Wrought, page 312) allows you to remotely project your consciousness into a tree you carved your face into. This is not specifically called out as a form of scrying, but it seems a good fit.
