I'm also an app developer, but have very few (if any) pirates using my games. However, I agree that if a large group of pirates downloaded your app, it would be worthwhile to take advantage of that increased user base (even if they're not customers). The problem occurs when the negative impact from the people who pirate your app (but otherwise would have bought it) surpasses the positive impact that the pirates make on your app (e.g. suggestions, more publicity, etc.) I'm pretty sure that there is a point where the negative impacts surpass the positive impacts.