[Triple]

Correct me if I'm wrong, but are not citizens who witness a felony authorized to make arrests?

Sedition carrying a penalty of up to 20 years is a felony - NO?

[Darksheare]

Yes.
However, the police need to show up and re-arrest them once they get there.
Usually, they'll just let the guy go since they did not see the crime 'in fact commited' in front of them. Otherwise, they'll take your statement, and if tehy think they can, prosecute you for unlawful detainment if they think they can get away with it.

Depends largely on teh state, and how the answering law enforcement officer feels when he gets there from the donut shop.
Or, in the case of Wallkill police Orange County New York, from their married mistresses' place.