One thing to keep in mind when it comes to the law is that there are two ways to address any issue. The first being the actual law, and using the law as it is written and accepted as a way to defend yourself (or to go after someone else, depending on what position you are in). This sometimes involves lawyers, courts, judgements, etc.
The second, and one that is far more prevalent than anyone truly realizes, is to bluff your way to getting your way. Many people, upon seeing/hearing a seemingly well-designed argument that looks and sounds legal will back off, fearing legal action. And, depending on how important this is, and how much your attorney will charge you, they'll go further and threaten using legal letterhead and a real lawyer. But notice that they haven't filed suit... Which generally means they either have a weak case, or they are bluffing. Again, most people will feel wary and threatened enough to back off and not pursue it further unless (like Freetrav) feel very, very personal about the issue. At times like that your zeal to defend yourself can be both a blessing and a curse. Generally speaking, of course.
Most laws are written so that if you take a little bit of time, you can unwind the legalese and figure out just what the hell they say/mean. And when someone threatens you with legal action, and especially if they did not provide the statute / law they are citing... chances are they are trying to bluff you into backing down. If the DO provide the information, then its easy enough to see if they are blowing smoke or not.
But the internet is your friend. As I posted earlier in this thread, YOU can easily research the law and see if what you are doing violates it (in this case, its Copyright law). A search engine should be your second best cousin. With it you can research case law, previous cases, previous rulings, etc. Don't be afraid to use it.
At the end of the day, this is all about a game. For MgT and Mark Miller, its also about commerce. So they do have a reasonable view (and legal position) to defend their business. In this case it would appear that no law was broken, no license violated. A simple request was enough to end the desire to share. But further review, and some squawking, seems to have shown that this was a "misunderstanding". Which is often how things like this get resolved.
There will be more of these incidents in the future, and that's good. Because it means that the user community is participating in the game and sharing for the enjoyment and betterment of all. This can drive interest, which can drive sales, which means the publisher is incentivized to continue to support the game.
Everyone wins (usually!).