I remember a discussion I had with a person in school a year longer than I. It was about some multi-state question about a person who was caught coming out of a house with a VCR that he thought was his. (In the night, of a house, etc. I think a fire resulted that killed people.) While we both agreed on the principle of the law (hence the correct answer), I brought up the reality of what would happen having been a police officer in the past.
The guy was going to get arrested.
Sure, there is a legal argument that can be made he is not liable. However, a guy watching another spray painting a wall is going to get arrested too. Is there a defense? Sure. But, if both are on a video buying the paint, both are driving to the place together, one is pointing while the other is painting, or, any of other facts that give rise to a joint project, the legal argument is going to be tough to win.