Plot hole: Someone entered Erin and Nicky's apartment, moved furniture, and disturbed photos. In the morning, Nicky is leaving the apartment to go to school, and she just opens the door without unlocking any of the locks or removing the door chain. It's NYC, and their apartment door isn't secured during the night or day, and ADA Erin Reagan doesn't think to question why the door is unlocked. (00:00:37)

Blue Bloods (2010)
1 plot hole in Occupational Hazards - chronological order
Starring: Tom Selleck, Bridget Moynahan, Donnie Wahlberg, Len Cariou, Will Estes
Dedication - S1-E15
Continuity mistake: At the start, Frank isn't wearing glasses at the table. Then in one shot he is. Then not again. (00:00:40)
Frank Reagan: And I don't have a Teflon suit. Everything gets to me. Every time one of ours is hurt, or jammed up, or he's in over his head, it gets to me. I just don't show it, 'cause I can't show it, 'cause nobody wants, or needs, a sensitive police commissioner.
Sid Gormley: OK.
Frank Reagan: So screw you!
Sid Gormley: Yes, sir. That an order, too?
Frank Reagan: Yeah, that's an order.
Sid Gormley: Screw me. I'm on it, boss.
Question: What is the significance of the lapel pin worn by detectives on Blue Bloods?
Answer: It is an NYPD Detective Bureau lapel pin. If you zoom in on a pic of "Danny Reagan," you will see that the pin has the letters DB on it.





Answer: It is the lapel pin worn by members of the NYPD Honor Legion.
The lapel pin is on Danny but not Biaz, why? Also, Baker, Sid, Frank &Garrett wear one. Significance? Are they all the same?
Is the P.C.'s pin different than a legion pin? What are the symbols and their meaning?
I think it may be Masonic?
But why would the mayor wear one?