I just thought about it and here's an example (and supposedly it's a real case):
A woman walks into a bar to ask for directions, or something of that nature. 2 guys won't let her leave and they do hideous acts to her, in front of everyone.
Some people cheer them on. Encouragement in many states is providing assistance, so these people are liable.
There was NO agreement to do the crime. Yet they're aiding and abetting, i.e., they're accomplices.
I hope this helps at least a little! Good luck!