In reality - in most systems (short of the larger counter depth Vikings and JennAire)...only the freezer is "cooled". You will notice a duct (probably behind a shield behind the top shelf). The cold air for the "cooler" side enters there. If you block access to that - things in front of it will freeze potentially (lettuce will be damaged). I prefer my milk as cold as it can get - thus, that is where I put my milk.
If you look at page 33 of this link
https://www.whirlpool.com/digitalass...%20Care_EN.pdf you will see the explanation.
This image (from the above *.pdf) shows where the air is vented from the frozen side to the chilled side
