what does the term "watch and learn. 'parking violation' is my middle name" mean? I saw it on a movie, and a officer said it to her friend.
'X is my middle name' is a trope, or general statement used to describe some aspect of your personality or attitute, or to emphasise that something is second nature to the speaker. A common example seen in movies and on TV is:
Danger? Danger is my middle name.
meaning the speaker is familiar with danger and is not afraid of it, and is often spoken by the hero of the show.
The expression is also often used for comic effect in movies, where a character makes a statement 'X is my middle name', before failing at X completely, which I suspect might be the case here.
A comedic response is often along the lines of:
Person A: X is my middle name.
Person B: I thought it was Bob!
which, looking at the subtitles for your movie, is the case.
Watch and learn. "Parking violation" is my middle name.
Really? I thought it was Rhona.