Under the Criminal Law Act 1997, when might someone be liable as an aider and abettor?

Under the Criminal Law Act 1997, a person may be held liable as an aider and abettor if they facilitate the commission of a crime in a way that contributes to the offense. Selling equipment used in a crime clearly indicates that the individual intentionally provided support that enabled the crime to be carried out. This act of providing assistance or support can fulfill the criteria for aiding and abetting because it shows participation or facilitation in the criminal act.

The other scenarios outlined do not meet the criteria for aiding and abetting. Merely being a bystander does not imply any involvement or intention to assist in the crime, and disapproving of the crime or being unaware of it indicates a lack of intention or participation altogether. Thus, the act of selling equipment aligns with contributory involvement, making it the only correct choice in the context of liability under the Criminal Law Act 1997.