It's possible, but extremely rare for a true false ban to be sent out. Riot tries to be sure it's an actual script and not, say, a firewall glitch.
They don't ban solely because someone gets mad and says another player is scripting.
The majority of players banned for scripting fall into three categories:
- Lying. They scripted and got caught but don't want to take responsibility
- Ignorance. They downloaded a program such as a skin viewer that includes scripted interactions
- Account sharing. They bought an account, paid for boosting, or gave a friend/acquaintence access to their account and the other person(s) used scripts.
For the rare, true compromised account (i.e. no evidence the player has ever scripted and has never willingly shared access) Riot has reversed scripting bans. But those also include the player's cooperation in proving ownership of the account and the only violations taking place during the compromised games.