Let's get back to the original point here. What, exactly, are you carrying that would subject you to arrest? Most people on this forum carry a folder, fixed blade, or pocket tool. Other than that, there is very little in your pockets/pack that would get you in trouble (maybe some strange looks, but that's been covered in other threads).

Some states ban knives over 3 or 4 inches, switchblades, etc. The law is usually written with exceptions for use in a trade, while hunting, or for some legitimate purpose. The exceptions are usually loose enough (and a policeman's understanding vague enough) that how you interact with him can be just as important as what you have on you. Well, unless it's a big honkin' machete.

Some things are against the law because they're bad, and some things are against the law because they're against the law.