Other mistake: Hawks is handed a pretty small container with some of the victims brains in it, and says there is about 50% of the brain still left out there to find. There is no way half of a brain is in that small container, it's not even filled all the way.
Other mistake: In the guest star credits, Shelly Cole's given name is misspelled "Sherry."
Other mistake: When Mac is reviewing the fact that the suspect has been researching his background, it displays a US Military separation notice on screen. The word 'separation' is misspelled as seperation, in caps.
Other mistake: Sid tells Stella that the girl in the martini glass died moments before the electrocution, except in the beginning of the episode you can see her dancing as she starts to be electrocuted.
Other mistake: When Adam shows Mac how Suspect X finds her clients online, Mac comments that he's thinking of phishing scams, but in the closed captions, the word is mistakenly spelled "fishing."
Other mistake: The body in the bank has one entry wound because the gun has no kickback, but in the flashback of the manager getting shot the shooter pushes the manager back then shoots him twice, the managers body moving alone would have causes the two bullets to enter at to different points.
Other mistake: Danny & Hawkes see a customer list on a shopkeeper's computer. Computer issue: Not only can she print the list and bypass a print option popup window with a single keystroke (implausible), but there are no icons/links on the page for software to do anything with that list. As well, the window scrollbar shows that there are nearly two pages of content on that screen, yet it appears to be a single complete page for the camera. Technical issue: The list contains 27 customer names - but one is repeated (Ryan Jackson). Later in the episode, they cross-reference that customer list (then printed on an opaque board in Mac's office, with that same duplicated name), against a company's employee list on Lindsey's pad computer. She was "able to notice one last name in common," yet there are three last names on the employee list also on the customer list, and one of those last names has two people listed - so that's four people who could have connections, yet only one was checked.
Other mistake: Mac is leaving a message for Christine. There is a close up of his cell phone. The keypad on the phone has the numbers in the wrong order. On every phone in history the first row of numbers is "123". On Mac's phone it is "789", like a computer keyboard.
Chosen answer: Probably to broaden the scope of the show's plot and give the audience a chance to see the characters in a different setting, People act differently at home from the way they do at their workplace. By the ninth season, the characters would have become overly familiar and predictable. It gives the writers a chance to do something different with them.
raywest ★