Well, Apple have managed it... It keys off the unique identifier of each individual computer. A chip on the motherboard of an arranger with a unique ID# would perhaps do the same thing. Then ethernet or USB direct internet connection could provide a secure delivery into a protected area of RAM, that the OS does NOT allow the file transfer system to read... A bit like IDC, but with protection, I would imagine.

I am not geek enough to flesh it out (I leave that to the company), and I have no guarantee that it couldn't be cracked, with sufficient determination. But despite the fact that DRM can be bypassed with great skill and effort, it hasn't stopped the iTunes store from turning around a planet's wholesale thievery of copyrighted music, and providing a simple interface and a reasonable pricing structure so those that DO want to play by the rules can do so, which has benefited both the customer, AND the industry that provides the content.

I imagine this would not stop the most determined from making MIDI files from the styles, and reassembling the style from the export. But this would take considerable effort, time and skill, which probably wouldn't be even attempted if the style, to purchase, was a buck or so...

This is how Apple have managed it. It's easy and cheap to get what you want legally (which it wasn't during the Napster heyday), so a vast number have chosen to use it.

I don't see why this couldn't work for the arranger...