is there some secret way they have of checking it's actually IPB and not some custom software masquerading as itThere must be some kind of weekly callback, I've never really checked though. I've always just kept to the free software. IPB is sluggish and 80% of the features are useless, vBulletin code is about as good as a trap door in a canoe. At least with the free softwares you know what you're getting.
Wouldn't surprise me if there were more than one script. That'd be what would make it hard to actually crack. Because removing only one script wouldn't be enough, there'd be other ones.
And then they could make somethings depend on the scripts, so you'd have to have the correct data in them. So on, so forth.
Anyways, yes, I'm very certain that IPB trys to get any hacked/cracked/stolen copy off the internet as soon as they can, but that doesn't solve their issue, obviously.