I have also worked through some iOS courses from Standford on iTunes U and I would not think twice about helping someone with one of the problems. Is that cheating?
Also, do you have any evidence that the no-cheating, no-publishing-homework policy is buried in a TOS? If Coursera hasn't made it obvious enough, then sure, people could have made a mistake. But Odersky's a smart guy so his reaction makes me imagine he made the requirement obvious.
A website that is providing you with completely free content from some of the top universities. I think it's fair for them to dictate the terms.