They can quite easily hit you with a federal conspiracy charge. Your IP on a list of "downloaders of LOIC" is plenty for a search warrant. A creative examination of your hard drive will come up with enough "suspicious material" to convince a grand jury. (Free lunch and $8 per diem is plenty to convince a grand jury.)
So, ok, you then claim you did nothing. The AUSA says "we do not believe you. We think you are an OP in Anonymous and are charging you with violation of 18 USC 1030 How's twenty years sound, hm?"
And conspiracy is so tangential, that anyone can be accused of it for pretty much anything. For example, I say to you "Hey dude! How about a free pound of coke!" You jokingly say something like "LOL sure dude, bring a big straw." And we both laugh it off. But you're neighbor overhears and calls the cops/DEA.You just conspired to buy a pound of cocaine. And you'd lose in court, like 97% of fed trial defendants. But I digress. This is the conspiracy section of the federal hacking law: .....
Whoever conspires to commit or attempts to commit an offense under subsection (a) of this section shall be punished as provided in subsection (c) of this section.
(c) The punishment for an offense under subsection (a) or (b) of this section is—
(1)
(A) a fine under this title or imprisonment for not more than ten years, or both, in the case of an offense under subsection (a)(1) of this section which does not occur after a conviction for another offense under this section, or an attempt to commit an offense punishable under this subparagraph; and
(B) a fine under this title or imprisonment for not more than twenty years, or both, in the case of an offense under subsection (a)(1) of this section which occurs after a conviction for another offense under this section, or an attempt to commit an offense punishable under this subparagraph; ....
Now, the AUSA says to you "ok, you have two choices. Go to trial, and I will beat you and you will absolutely do at least fifteen years. Or sign this admission of responsibility, plead guilty to this minor count and do five. Your choice."
Many people say "I'll fight!!" Almost all of them will reconsider that as they pass year 12 at Fort Dix.