I disagree with Daniel here. I believe it is a matter of one's own mindset. I do not believe in Chaotic acts, which implies to me that chaos would have some sort of judgemental intellect which, being a primal ooze, it does not.
One's own mindset is the thing that takes you to places on the Heroplane, that summons chaos to you in your Otherworld. That perhaps leads you to sacrifice to some hole in the void rather than a sane deity of the Cosmos.
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> I don't think it's really a matter of one's own mindset, though - the current view seems to be that Glorantha's magic is a bit more objective and solid than that. It is a matter of culture and proper rituals, however.