can we add an explicit test for the "we don't get screwed by active support" case? I'm thinking something like define a method on Kernel, like:
```ruby
module Kernel
  def this_might_be_defined_by_bad_monkey_patch_people
     raise "Sad Panda!
   end
end
```
And then make sure that configurable hides that from you.

I think it helps to be explicit in the kinds of cases we're addressing.