I wouldn't worry about it. With iOS apps, it's much easier for people just to buy your app and have it installed and running on their device than it is to try a

I wouldn't worry about it. With iOS apps, it's much easier for people just to buy your app and have it installed and running on their device than it is to try and pirate it, so unless you're seriously overcharging for your app, most people will continue to just legitimately buy and use it. You could also charge a small recurring service fee for accounts and then give the app away for free.