The terms of use are a beta as the rest of the service. There may be bugs or parts where we have been hyperprotective or uncler in our intent.
Let me understand better your needs.
The rude question that pops to my mind for you is "Why would you rather serve stale results?"
The reason why this constraint is in the present ToU is that we want to make it impossible for you to serve last week's news from your cache as the "breaking news" (this is an extreme case, but it drives the point - the same is valid for web search where you'd miss on the latest blog posts, for example).
If your app has special needs do not hesitate to contact api_tou at microsoft dot com requesting an exception and explaining why.
HTH
--Alessandro