A violent criminal is anyone who is willing to use force or threat of force to impose their will on you. This includes all situations with or without a weapon. Remember, their willingness to confront you tells you that there is nothing they won’t do to get what they want. They are not to be trusted, no matter how convincing. Criminals and thugs don't care about the law, they don't care about Judges, they have no morals and they don't care about you or your family.
In order for anyone to impose their will on you, they need to get close to you. Use of weapons increases their sphere of influence, but just the same, they need to get close to you in a manner that does not draw attention to the crime.
Criminals are cunning and not to be underestimated. They will use a variety of reasonable and plausible requests to close the distance on you. Anything from asking directions to asking for the time, they will use tactics designed to distract you. They will have accomplices that you don’t see. They will provide reasonable explanations that will get you to do what they need.
The criminal picks victims based on ability, desire and opportunity. If you look like a good target, and the risk of your attacker getting caught, identified or injured is low, they will strike. Remember, the more desperate they are, junkies and emotionally disturbed people the more brazen they will act because their desire to get what they want will override all other factors in the criminal equation.