In the episodes where the blood is spattered or in a large pool, the pattern of the blood varies from scene to scene. For example: A person is killed and the blood is sprayed across a desk. The pattern in scene 1 (finding the body) will be different than in scene 2 (going back to the crime scene for further evidence).
"The CSI Effect": CSIs are not detectives as this is exceedingly rare in real life, as they are actually classed as civilian employees. It is considered an inappropriate and improbable practice to allow CSI personnel to be involved in detective work as it would compromise the impartiality of scientific evidence and would be impracticably time-consuming.
In many episodes, a suspect is found because a gun was registered to them or someone is threatened with the charge of "possession of an unregistered firearm", or some other reference is made to a firearms registration database. The state of Florida has fairly relaxed gun control laws, and there is no gun registration system anywhere in the state.
When the CSI's and detectives are interviewing someone or working crime scenes, they are never seen taking notes or sketching the crime scene. Real CSI's and detectives are constantly taking notes and sketching. The notes and sketches are so important that they are occasionally booked into evidence to ensure the originals will be available for review before trial.
"The CSI Effect": In many occasions, when arresting a suspect, Horatio's team is able to exact a confession but never the Miranda's right are read to the suspect, which can and will be used to render the confession unusable in a court of law.
On numerous occasions, suspects are given a "perp walk" from the front door of the police building to a waiting squad car or jail bus. While this provides for good drama (reporters, angry relatives of dead victims, etc.), such prisoner transfers are supposed to take place away from public view, to avoid the public spectacle portrayed in the show.
The same line pattern (which looks like an off-center 5-pointed arch) is consistently used when the CSI's try to search for a fingerprint match in AFIS.
Miami has a subtropical climate and is often very hot and humid, especially from late spring to early fall. There are numerous episodes which occur in the summer and fall months where it's clear from the clothing worn by characters that it is much cooler than it would be at that time.
Many times during different episodes you can see people that are supposed to be dead breathing or moving.
During many of the episodes, we often see an overhead shot of one of the CSI's in a Hummer speeding down the Miami Highway to a crime scene etc. If you pay close attention, there is almost never any other traffic on the highways besides them. Very unlikely if not impossible, especially in Miami.
In many exterior scenes, California hills are visible in the background. South Florida is mostly flat.
When they refer to the Dade County Jail, we are shown an aerial view of Everglades and Dade Correction institutions. These are two state run prisons located adjacent to each other in Dade county.
Southern Florida is a coastal plain. While there are often hills shown in the series, in fact Dade County's (the location of Miami) highest elevation is 42 feet above sea level which is barely perceptible and is well inland from the coastline.