In the USA, it's not illegal to translate a private data format into some other form, nor is it illegal to copy the data if it consists only of public facts (like political boundaries, shorelines, mountain top locations, even roads and building locations. Where you get into trouble is when you also copy private data. This is usually in the form of maybe small bits of fake datum and since it's not public information, if you get caught with that in your copied data set, you're screwed.
My favorite method for embedding private information in a database is called steganography (hidden writing.) It's a method where you use an encryption routine based on the data, that's stable against normal GIS operations (scaling, projection) as well as attempts to wipe it out. This "fingerprinting" gives you a reasoable chance to win a lawsuit because you can claim that the fingerprinting itself is private data and if the dataset was copied, the fingerprinting was too. You demonstrate that by running your translator over the suspect data, and as you get back the message you claim to have embedded, the judge and the jury's jaws drop in amazement, you have a Perry Mason moment, and the copy cats' defense crumbles into the dust as they beg for mercy.
BTW, this legal advice is worth every penny you paid for it. If you're making big decisions for your business that may have legal consequences, hire a real lawyer first and follow their advice. Otherwise, you'll find out why the Internet enjoys the reputation that it has as an unimpeachable source of information.
- Bill Thoen