That's the trouble with so many of our laws. They are either so wordy with legalese that a layperson can't understand them, or they are so vague that no one can interpret them. Even when the intent of the law is clear to a reasonable person, if it isn't written precisely enough, it can be difficult to enforce or to come up with a valid defense. I once read about a case where someone was arrested for possession of a certain street drug. When the case went to court, they were unable to convict him because when the law was written, they used the scientific name for the drug and misspelled it. Therefore, there was actually no law against possessing the drug that he was arrested for having.
One good thing came from the passage of the Concealed Handgun Act (well, lots of good things, but): the term concealed was actually defined. Prior to that, it was pretty much up to the individual police officer, or judge, to decide if someone was carrying a concealed firearm. To some extent, there is still some ambiguity, but at least we have a definition of some kind. Basically, the law says that if any part of the gun is visible, it is not concealed. That seems pretty cut and dried. However, no matter where or how you carry your gun, it is probably not visible from every possible angle. If you have it in an open holster on your right hip, and a cop is standing on your left side, it is not visible to him. I know that seems like a pretty ridiculous example, but when it comes to judges, lawyers, cops, and juries, nothing is too ridiculous to conceive.