Comments from Clinton Nixon:

"I really thought I talked in the rules about the possibility of the Story Guide calling a contest as "harmful" before the roll, stating that the loser will take harm. But, I just looked, and I don't see that. Hm. Anyway, harm only happens in BDTP unless stated otherwise by the rules, or by the Story Guide in a specific situation. (For example: you've got a field full of broken metal and glass that the characters are going to charge across. The Story Guide might say, "Make an Endure check. If you fail, you reach the other side with Harm 1.")" [1]

"Unopposed checks are a place that I'm never quite happy with the system. It's hard to threaten harm, as with an unopposed check, you'd have to set the level of harm yourself up-front instead of making a roll. I'd say that if a physical obstacle really is that significant, give it Power." [2]

Comments from Eero Tuvoinen:

"... this is one of those things that should have been touched on much more clearly in the book. What follows has all been confirmed with Clinton in one or another of these forum discussions. Actually, I'll find a link. To summarize:

"In TSOY the Story Guide is the guy who calls the stakes. What this means is that while the players will declare their intentions, the SG will confirm how these go into stakes. This is a necessary function for several reasons, one of which is that ultimately only the SG can make the call on how an ability use translates into a reached goal. In some circumstances a character can destroy the world with one conflict, for instance, but this is not the case always. That's why it's up to the SG to make the call about what, exactly, a character can achieve through the conflict at hand. Most of the time it's exactly what the player wants, but some times he has to succeed through several conflicts before getting there. (I'm only harping on this because previously this has been a problematic point.)

"Anyway, one of the horribly underrepresented-in-the-rules options the SG has is to declare Harm as a part of the stakes for one or both sides of the conflict. This is completely up to SG consideration; I personally recommend using it to underline the gravity of situations, and using it pretty often, much more often than most of us do. My own S Guiding? would be better off if I learned to add in the Harm more often, for example. (Yes, it's not mentioned in the rules outside the examples. That's why it comes up now and then.) This is a very useful mechanic for making the Harm rules count for more; without, they kind of hang half-utilized as the latter part of BDTP complex.

"When declaring Harm stakes, the SG sets the resulting level of Harm before the conflict, it's not worked out based on the results of the roll. An important point to consider are different secrets that allow the player to call Harm into the stakes. For instance, the Secret of the Hidden Knife and the threecorner ability of Destruction both explicitly allow a player to frontload a conflict in this manner. Usually, however, it's up to the SG." [3]