According to urban myth, when you move around London, you will be caught on CCTV (close circuit TV cameras) up to about 300 times in any one day.
So why is there no CCTV in the USS Enterprise? When Geordi laForge calls the Bridge to say that there is something strange on the sensors when he scans Cargo Bay 2, a team of security red-shirts is dispatched to go and use the Mark 1 Eyeball to investigate, and they probably get sucked into an interdimensional vortex, get eaten by something that transported itself onto the ship, or they find another one of Wesley's damned nano-robot experiments gone haywire again. Either one of those OR there's nothing wrong, expect for Geordi's stupid sensors. He should have gone himself and used his fancy sunglasses-gadget to see what was going down.
HOWEVER, if the bridge crew had simply switched the CCTV on in Cargo Bay 2 - probably Ensign Bored's job - they would have seen the pile of tribbles, or whatever, and known if it was safe or not to send a red-shirt to arrest them.
See, makes so much sense. Oh wait, I forgot... it's a plot device. It's only a TV program after all.
So there you go, Rosemary, why CCTV isn't deployed on the Enterprise.