At the suspect's house, the blueprints list the blood bank address as 2201 Oriole Lane. However, when Shawn, Gus, and Jules drive up later that night the address listed on the sign attached to the building is listed as 221 Oriole Lane.
When Lassiter holds the necklace at the crime scene, some of chain is caught between his fingers in a couple shots, but not in most others. In the final shot the way he holds it changes completely.
(at around 26 mins) Carlton is asked if he's wearing garters, the camera pans down and they are tautly connected to both his shirt and socks. When Carlton turns and walks away they are no longer attached to his socks, dangling freely from his shirt.
This episode greatly exaggerates the rareness of O-negative blood, claiming there are only about 24 people in Santa Barbara who have it. O-negative is rare, yes, but not THAT rare - estimates range from 6.6%(Stanford School of Medicine) to 9% (American Association of Blood Banks) of the U.S. population has it. With a population of about 88,410, there should be about 6,600 people in Santa Barbara with O-negative blood. (The audio commentary on the DVD addresses this error: Steve Franks, the show's creator, states that many fans pointed out this mistake in message boards. He blamed Wikipedia as the source of this incorrect information.)
Chloroform doesn't knock someone out instantly like it did to Gus. In reality, chloroform actually takes a while to effectively produce results.