The Uniform - S2-E11
Character mistake: While handcuffing an auxiliary officer in his apartment, there is a poster on the wall reading, "attention military personal..." Personal is misused. It should read "attention military personnel." (00:16:02)
Character mistake: When Henry and Jamie are putting away leftovers from dinner, Jamie puts food in a plastic container and then puts the dirty fish in the cabinet with the clean dishes.
Continuity mistake: Frank and Henry are up late, 3am, and, talking about how his late wife Mary never wanted to see her youngest go into the Family Business. Henry says how proud Mary was in the day of Jamie's graduation. But Mary was already dead by the pilot, when Jamie graduated.
Parenthood - S2-E14
Continuity mistake: Frank moves his foil wrapped sandwich from sitting on top of a stack of blue folders on top of a newspaper. However, when he reaches for it the sandwich is back on the stack of blue folders. (00:10:07)
Visible crew/equipment: At the start of the episode, the first character (Cole) has an audio wire sticking out the back of his suit. It disappears in the next shot. (00:00:25)
Answer: It's a common cop show plot device. If the police on the show always acted in the most logical way (i.e. not alerting a suspect to their presence) the show wouldn't have the opportunity for an exciting foot chase.