Blindspot CCTV

A normal CCTV camera, angled slightly downwards, surveys the area. Meanwhile, hidden to the hard-working piece of surveillance equipment, a despicable hooded fiend, known only as a delinquent youth, stands underneath the poor device spray-painting "i r dat guy wot roolz i is" on the wall. Of course, it's only by fluke that the flatulent idiot stood underneath the camera, he's far to stupid to understand what a camera is unless it's explained as a "A box that watches stuff and remembers it so you can see it again, alright man?", but still, the innocent CCTV equipment gets blamed for not noticing the retarded scrawlings of the brainless oaf beneath. Unless of course, that CCTV camera is fortunate enough to have another camera within it's mountings aimed downwards at the blind spot.

Of course, this doesn't really have the greatest applications in catching moronic loiterers desecrating walls with their incoherent drivel, but it was merely an example. It would have greater applications in areas of high security, such as embassies and the like, so that spies who think they're clever by using the blindspots to go unnoticed can be caught with ease. Or at least with the use of a laser beam, an elaborate death, and several ridiculous puns and catchphrases. No doubt they were just "Keeping the British end up", or "Attempting re-entry". But certainly, they would be caught by the blindspot camera.