Nobody is going to arrest you for "curiosity" but they might arrest you for bank tampering because somebody might you know have their life savings in there.
Also, "illegal" is not a constant, often arbitrary and usually serves only the interests of those that want to maintain the status quo.
If curiosity and creativity was constrained by what happens to be illegal at any given time, our society would look a lot different, and not for the better.
It's this sort of fear mongering that got us here.
The catalyst for me getting out of the black hat side (other than aging out of the 'being bad is fun' stage) was getting into a massive system from which I could have easily pilfered millions. Thoughts of everything from "set up Swiss bank account, fill up" to "offer to 'consult' with the company in question to fix the holes" went through my head. In the end, I just said "game over, I won," stopped cracking systems, and put up the Phoenix Project BBS as a center of learning. Which lasted until the Secret Service showed up at my door in 1990...