Show What You Got
For anyone to join a biker gang it is not enough to just go through the flaking period with success. The potential candidate has to show all he has got in order to be considered worthy of joining. Some biker gangs have crazy things in their mind for their prospective members.
To prove you really want to join, the biker gang may ask you to commit a crime that may or may not include hurting a member of another gang or sometimes even a citizen. The point of using violence in this period is to test the loyalty of a person to the gang.