This message is an attempt to clarify the issue. I am not a lawyer, don't play one on TV, didn't sleep at a Holiday Inn Express last night, etc.
Provocation comes up in a legal context related to Penal Code 9.31, which is the justification for use of force—not deadly force: "(b) The use of force against another is not justified: (1) in response to verbal provocation alone;..."
This section of the law is the foundation for other uses of force or deadly force, which refer to it as a prerequisite.
There are very clear examples of provocation. The typical "Who you lookin' at" or "Yo mama" jibe is a verbal provocation. The finger is not verbal, but is in the same category.
It is never provocation to tell someone to stop doing something illegal. If it was, the cops could only hand out little cards asking people to kindly refrain from robbery, rape, theft, vandalism, etc.
This pertains to personal assaults, theft, trespassing, or any other crime. Also you have the right to tell a person to leave your property for any reason. You can even tell your mother-in-law to leave, if you want to deal with the consequences.
The gray area, as I see it, is when another person starts to escalate a situation without actually committing an offense. For example, if you accidentally bump someone, and he goes off like a firecracker. I have had this happen. My solution is to apologize profusely, far more than etiquette requires. This has always worked. These people have a fragile ego that needs to be reinforced.
Your comments are welcome (as if I needed to say that

- Jim