I've never felt the need to do a specific interpretation of % values. But I'm actually kinda happy Jason says this IS in the new rulebook, as it will least shut some detractors up.
Of course - I know people will now debate the interepration, probably ad nauseum
I too have applied modifiers under certain circumstances. As to whether a person with a 0% had a chance to do something anyway, it depended on the skill and the circumstance. I'm a seat-of-the-pants sorta GM. I always thought BRP lent itelf well to that. One of the reasons I like it.