Each person inclined to effect citizens arrest should understand the laws Federal, State, and local before attempting this(don't forget to read all case annotations). Unless it is absolutely criminal, ie committed robbery or burglary, murder, severe battery, etc. right in front of you, you are risking your freedom and everything you own including your right to bear arms.
I have played the "scenario game" with citizens arrest. The circumstances which I would/have executed a citizens arrest are few. I have executed 3 citizens arrests in the last 15 years. I have consulted with several of my attorney clients about this issue. I have read many case annotations related to this.
I believe with the realities of civil and criminal legal authority/decisions, citizens arrest should be left only to those who maintain significant "Errors and Omissions" insurance policies specific to citizens arrest. Security companies, armored car personnel, private detectives, bounty hunters, private process servers, etc. Some general business liability policies allow coverage for limited citizens arrest by the policy holder(bars for their bouncers, mall security). Anyone who is covered by such a policy knows (or should know) the limitations of their coverage. Most are trained to be a good witnesses and leave arrest to LE.