An anonymous comment to my post on who owns genealogy said, "Its true that names and dates aren't "ownable", but if someone writes up their family history in a narrative format, it is copyrighted, and any reproduction without permission is illegal." Fortunately, we do not yet have copyright police in the United States. In fact, there is no agency at all, in the entire government, that enforces copyright claims. The comment shows a very common misconception, blurring the distinction between civil and criminal law. Criminal laws are those enforced by some level of government that have criminal penalties for their violation. For example, theft with a penalty of a possible jail term. The state (city, county, state, or Federal government) is always the plaintiff or complaining party in a criminal action. A jail sentence can only be imposed for violation of a criminal statute or law.
On the other hand, statutes like the copyright law, may or may not impose criminal penalty. Almost all of us are familiar with the annoying FBI notice at the beginning of any movie on a DVD. That notice is a reference to a criminal violation of the criminal law of copyright. Most, nearly all, violations of the copyright law do not result in any criminal penalties. When we speak of some activity as being "illegal," it can only be illegal if the activity has a criminal penalty. Copying someones genealogy file, even their "family history in narrative format," is not illegal. The statutory provisions give rise to a civil claim for monetary damages and perhaps, for a court order prohibiting the copying (injunctive relief). So if you tell someone that it is "illegal" to copy a file, what you really mean is that if you do so and you suffer damages, you may be able to bring a lawsuit in the Federal Court to prevent the person from copying your works and for damages you may have suffered.
It might also be important to note, that there are several prerequisites to filing an action for copyright infringement in a Federal District Court. The first is that the Federal Courts have original jurisdiction in all copyright claims. That means you can't sue someone for a copyright violation in a state or county court. Next, you have to register your work if you wish to bring a lawsuit for infringement of a U.S. work. To quote the U.S. Copyright office, "Registration is recommended for a number of reasons. Many choose to register their works because they wish to have the facts of their copyright on the public record and have a certificate of registration. Registered works may be eligible for statutory damages and attorney's fees in successful litigation. Finally, if registration occurs within 5 years of publication, it is considered prima facie evidence in a court of law. See Circular 1, Copyright Basics, section “Copyright Registration” and Circular 38b, Highlights of Copyright Amendments Contained in the Uruguay Round Agreements Act (URAA), on non-U.S. works."
Perhaps, you should read some of the descriptions of copyright laws before you tell someone what they are doing is illegal.