We report a series of sentence-rating experiments designed to test the recent claim that pied-piping of PPs in English is an instance of ‘massive pied-piping’ (Heck 2008, Cable 2010). We find that the relatively subtle judgments informally reported in the existing literature on pied-piping can in fact be replicated in a formal experimental setting. The resulting data support the claim that (unforced) pied-piping of PPs in English is a para-grammatical phenomenon, and that P-stranding in English is (essentially) obligatory where it is possible (Heck 2008). Furthermore, these studies provide further evidence that informally reported judgments - even very subtle ones - can indeed be rigorously replicated using formal experimental methods.