The failure to even protest is equivalent to encouragement and is fatal to the appellant’s defence.
Not every passenger in an unlawfully driven motor vehicle is necessarily subject to conviction as an aider and abetter. Some passengers may not have the same authority over the car or any right to control the driver. In this situation, the passenger did have the authority.
Dunlop and Sylvester v. R.  2 S.C.R. 881
Gang rape of a 16-year-old girl at the hands of 18 members of a motorcycle gang. The accused were members of the gang but the evidence shows they had gone to get beer and were sitting nearby when the rape was going on, which they thought was consensual sex with one member as the others stood around.
Was there enough evidence to permit the jury to draw an inference that the accused were more than merely present at a crime and had done nothing to prevent it? Will a man’s presence at the scene of a crime without trying to prevent it suffice to render him liable as an aider and abetter?
No and no. Appeals allowed; acquittals entered.
A person cannot properly be convicted pf aiding or abetting in the commission of acts which he does not know may be or are intended. If there is no evidence of encouragement by him, a man’s presence at the scene of a crime will not suffice to render him liable as an aider and abetter.
The evidence in this case only went to presence and not complicity.
R. v. F.W. Woolworth Co. (1974) 18 C.C.C. (2d) 23 (Ont. C.A.)
A man named Healy entered into an agreement with Woolworth for some floor space and use of the cash registers in one its stores in order to sell some ballpoint pens. Healy made misleading representations regarding the price of these pens and Woolworth was held to account.
Can Woolworth be convicted for aiding and abetting?
No. Appeal allowed; conviction quashed.
There is no evidence that Woolworth had knowledge of the facts which constituted the offence. Even if someone incidentally and innocently aids another in the commission of an offence, that’s not enough to involve the alleged party whose purpose was not that of perpetrating the offence.
Gamble and Nichols v. R. (1978) 40 C.C.C. (2d) 415 (Alta. C.A.)