I think that the legal theory is that possession of certain items is indicative of bad intent.

If I carry x quantity of illegal drugs, I'm a user getting charged with a misdemeanor. If I carry x + y quantity of illegal drugs, I'm presumed to be a drug dealer.

I'm just explaining the thought process -- not agreeing with it. Unlike drug sales or burglary, the most important tool for hacking is whatever is in your head.