Aranfan
Team Plasma Grunt
Can you explain why? We have multiple independent sources that indicate this is both legal (if sufficient to raise eyebrows amongst those poorly informed about the topic) and not going to corrupt us. These sources have both personal experience with the practice and a long history of outside verification that they're not corrupted, and there isn't any evidence that I'm aware of which contradicts that, so I'm not sure how you're reaching that conclusion.
I just don't like the idea of binding warp entities. It smacks too close to slavery for me, and its close enough to daemonology that if the witch hunters catch wind of it they'll want the hat back.