Continuity mistake: The business card given to Dan Zavitz by Bobby Dean in the lingerie shop is not the same business card removed from his pocket by the agent after he gets hit by the fire truck (second timecode). The email address along the bottom of the card has changed, In the first shot, it's 'rdean@next.net' and in the second it's 'rdean@silverbergblake.com'. (00:25:00 - 00:26:45)
Continuity mistake: In the scene in the lingerie store Will Smith is talking to a blonde assistant. She has a piece of her hair tucked up behind her ear, but as the shot changes her hair is down loose again. When the shot changes again the piece of hair is behind her ear again. This happens roughly about 3-4 times.
Continuity mistake: When Jason Lee gets out of his car to his video hutch, the driver's side window can clearly be seen to be 15 cms or so wound up. When he returns to the car with the incriminating tape in hand, the window is fully down.
Continuity mistake: After nana picked up Will's kids and Will Smith is lying in the back of the car, look closely at nana's seatbelt. In the first shot it's on, in the next shot she doesn't wear it anymore and in next shot its on again.
Chosen answer: The fake Brill is an undercover federal agent trying to find out what Will Smith knows about the video tape.
Mister Ed
Poor writing though as that character is never spoke of again.