There's a problem with Geasa, one that makes a low-level Geas far more dangerous than a high-level Geas: Frequency of Retribution. A Geas/1 inflicts Dissonance a lot faster than a Geas/6, and in cases where one can't fulfill the Geas, the Geas/1 can be a quick trip to Disaster. Here's a set of house rules that deals with that situation.
Merely a hopefully-clear statement on my poilicies on Disturbance emission and propagation in my campaigns. Hopefully, these are sufficiently clear to make sense.
"Took you long enough. Been waiting on that Disturbance thing since what, June?"
"Had some thinking to do about it, and its implications. It's still not in a final version, just in a version good enough to post. Reasonably complete, at any rate."