That's true. I agree, you should iterate over all your existing capabilities and drop those that are not in the white-list. (I have implemented this functional

That's true. I agree, you should iterate over all your existing capabilities and drop those that are not in the white-list. (I have implemented this functionality in one of my projects this way.) BUT: Maybe the reason some people do it otherwise, is that capabilities API have only a drop function for the bounding set, and people just don't think they should use it in reverse mode - Sapir-Whorf Hypothesis in operation! ;) edit: seems like the author have a different reason though