You don't get LeaverBuster for leaving one game. Riot does take into consideration things like the power going out and will assume it's one-off. It took at least 5 games of me disconnecting to get even a 5 minute LeaverBuster, which includes the actual intentional disconnect before I figured out how to mute people. You get LeaverBuster for a pattern of behavior.
Learn to use the mute function. It's amazing.
Just like LeaverBuster Riot will assume a bad game not feeding. It's the pattern of behavior that gets you in trouble.
You won't get punished for false reports. If you do nothing wrong (as defined by the Summoners Code and Riot TOS) you won't get in trouble no matter how many reports get put against you. Remember 1 report counts for the same as 9. You will only get banned for your actions.