The clip you see above owes a heavy debt to the Discovery Channel's Mythbusters. The premise here is the same: Present demonstrators with a seemingly implausible in-game situation, test said situation, then report on the findings.
As a result of this rigorous testing - which, granted, could have been faked for unknown reasons - we now know a number of new things. For instance, guard dogs will attack one another if there are no heavily-armed people nearby to maul. Even better, though, is a sequence at the 2:00 mark, where our demonstrators test the idea that a sniper could kill a person by bouncing a shot off of one of the game's riot shields. Conceptually, that's as awesome as it is silly, but as the video demonstrates, it totally works.
This clip is the first episode of Call of Duty: Ghostbusters, so expect more such efforts until the community grows tired of having their fanciful notions crushed by cold, hard facts.