So... really strict rules for running on Microsoft's ad network, but nobody cares if you're running on someone else's network?
Seriously though they can't win - enforce this, everyone goes elsewhere. Enforce this for other networks, expect lawsuits.
Never an MS fan but they're at least trying to do the right thing here. It'll probably be the death of their ad network, though. Which, given that they're trying to make ads behave nicely, is a shame.