Most crimes require intent, hacking is one of them. The relevant law in this situation is:
> (a) Whoever— (2) intentionally accesses a computer without authorization or exceeds authorized access, and thereby obtains— (C) information from any protected computer; shall be punished as provided in subsection (c) of this section.
So if it can't be proven that you intended to access a computer without authorization, or exceed your authorized access, then you can't be found guilty of the crime.
Consider the possible consequences of the law not requiring intent, if simply accidentally exceeding your authorized access could be a criminal act.
> (a) Whoever— (2) intentionally accesses a computer without authorization or exceeds authorized access, and thereby obtains— (C) information from any protected computer; shall be punished as provided in subsection (c) of this section.
https://www.law.cornell.edu/uscode/text/18/1030
So if it can't be proven that you intended to access a computer without authorization, or exceed your authorized access, then you can't be found guilty of the crime.
Consider the possible consequences of the law not requiring intent, if simply accidentally exceeding your authorized access could be a criminal act.