Yeah, that's terrible. I'm all for anti-piracy measures that mess with the app when it's pirated, but to assume that "jailbroken" means "pirated" is dumb. I've jailbroken several iOS devices and never pirated any iOS software. You can pirate iOS software without jailbreaking.
This is the problem with "detecting" piracy - it is super-easy to get it wrong and start punishing legit customers. Any developer who makes the decision to punish pirates risks losing paying customers. How many lost paying customers is it worth it to punish people who have never and very likely will never give you a dollar?
I love the approach that showed up recently where the developer uploads their own torrent to pirate sites. The torrent has the game, but it's a slightly-modified "pirate version" rather than the regular version. You can beat any pirate group's release time, and if the modifications are subtle, people won't notice until the torrent is already entrenched. This has pretty much zero risk of punishing legit customers unless you cock up your build process and accidentally ship the "pirate version" to them somehow.
Stuff that tries to detect piracy by looking at its runtime environment or whatever is bound to go wrong, of course.
Yes, but each account can put apps on a hundred devices. You can buy signing keys for a single iOS device for a few bucks from shady people with developer accounts who are selling their device slots off one by one.
