If you have dealt with assembly loading, chances are you have asked this question:
How do I know which assembly CLR will really load if I ask it to load some assembly?
In Whidbey, we introduce AppDomain.ApplyPolicy. It takes an assembly identity string as input, evaluates binding policy, and returns the post policy assembly identity.
It does not tell you which file CLR will load. But at least you are confident about the assembly identity.
It is an instance method on AppDomain class. So you are able to evaluate the policy on any appdomain.