Happened to have one on my Citrine relay. Looks like they are indeed plain-text, so relay operators do get to read them and watch your thoughts come in live.
Discussion
They should add a feature to fetch other people's drafts too, that way you can start typing a counter argument to what they are saying before they have even posted it. As a bonus, even if they corrected any spelling mistakes before posting, you still have an opportunity to make fun of them for having typed them at all.
Hmm, maybe I should start running a relay...