Slight chance of horor mark(O really)

[Xietor]

Manual claims that there is a "slight" chance of a horror mark from certain items. And I was told by someone that "slight" means 5 percent.

However, in actual game play, the Robe of the Magi inevitably horror marks my mages after 1 turn, as does forbidden light.

I would respectfully submit that there is in fact more than a 5 percent chance of a horror mark when these items are equipped. In any event, the word "substantial" or "inevitable" should be substituted for "slight" in the manual if no change is implemented to the percentage chance of getting horror marked from these items.