Yes if he is acting in good faith. That is the problem with your arguement. You lump Coppers doing their jobs to the best of their ability and having an "oh excrement" moment with knowingly breaking the law.
For example, ol' Wagonman hears a flash describing a White male 20-25, black jacket, blue jeans wanted for Armed Robbery.. Ol' Wagonman sees a guy matching said description in the same area. Ol' Wagonman stops the squad draws his XD45 Tactical orders suspect at gunpoint to kneel and put his hands up. Ol' Wagonman glances at his reflection and thinks "heck yeah". Ol' Wagonman then closes on suspect he starts to rise ol' Wagonman giving good verbal instruction probably using language that would rate a suspension from TFL. he continues up, the fight ensues and suspect sustains a broken jaw. While this is occuring the REAL offender is grabbed. Now the suspect is nursing a broken jaw and a resisting charge.
Dust Monkey would want ol' Wagonman charged with false arrest and Aggravated Battery. "Color of Law" be darned.
How dare ol' Wagonman abuse his power and beat on an innocent man.
Your arguement crumbles under it's own weight.