In "The other guys", Allen says:
Anything you say or do can be used as a floatation device.
What's funny about it?
Allen Gamble (Ferrell) forgets how the Miranda Rights speech goes, so his partner (Wahlberg) jokingly makes him finish the sentence with a bit from another familiar speech: the saftey speech in airplanes that at one point tells you that certain things around you could be used as a floatation device. Thus, he's making Allen sound like a flight attendant rather than a cop.