There is a tradition in fiction at least of Hexensnacht being a time when chaos powers whisper etc.
What do you think of ruling that someone making any important roll on that night, including recovery and disease recovery checks, and rolling a Chaos Star might get a whispered voice offering them aid, automatic success, recovery etc if they "accept my/our/your blessing".
The blessing would be a big dose of corruption points (4) or what...?
Refusing the offer would invoke a "curse" of some sort, the Ill-Fortuned condition for a month perhaps?
Not sure about this but trying to figure out how to reflect this in the game, including the capricious and unfair nature of Chaos' attentions but still reflecting game balance because purely arbitrary stuff is not really kosher in an RPG (in my view at least).