I can chalk the evidence tampering up to her just bluffing, but everything else she did before that, like at least 2 occasions of black mailing, is what really annoyed me. I still think with everything the writers thought up, and the way the character is acted, she still doesn't really deserve to be Black Canary. I would have been fine with Laurel eventually suiting up as the Canary, because she realizes being in the Courtroom isn't enough to help people.
She didn't need her personal "Island" in form of boozing and taking drugs, generally being a complete b**ch in Season 2, and then sacrificing Sara to justify her suiting up. Yes, no one becomes a hero over night, but the whole starting out as a Hero could have been her Island, her trials to overcome. I wonder if we can actually ever get a hero on the show, who hasn't been completely miserable and hasn't suffered any kind of personal loss.