You can't stop pirates and converting users of the piratery is not worth the effort. I hope this doesn't drain your revenue, but if you can just push forward and make paying customers happy and find new ones, that's where I'd spend my time.
Probably yes. I'm just curios. I've seen people probing for files outside the sandbox to detect if someone runs on a jailbroken device. Wonder if Apple would reject those because of "hacking".
I imagine that if you disable the use of your app by paying customers, the damages you will incur will dwarf the pain you feel from piracy.