At the Thursday signing I asked: "When Khriss visits Scadrial, does Harmony know it?"
Brandon wrote in my book: "Some times He does. (more often than not, these days... But it is [emphasis Brandon's] possible to hide.)"
After writing that he told me (not a direct quote) that Khriss doesn't have a lot of reasons to hide (he seemed to imply that some others would want to hide more than Khriss does). She doesn't mind the attention, usually.
I assumed he was referring to Hoid or the other beings that are visiting Scadrial, but he didn't actually say that.