User blog comment:Emptylord/Season 3 - PBE Patch Notes/@comment-89.106.167.109-20121123101032/@comment-5490997-20121123122531

I'm guessing it doesn't work with Runaan's because pickpocket has a 5 second CD. So when it hits an opponent it's on CD for any other targets it might hit.

It probably works fine with Parrrley, but I doubt the utility tree is worth it for him if he goes top or jungle. He might be able to support, but I personally am not a huge fan of support-plank and I don't see why using it with Parrrley would be any advantage over normal auto attacks (with Soraka for example).