I agree that some care would need to be taken to ensure that the redshirts felt like active participants in the joke rather than the butt of it, but at least in a reasonably informal environment it could, in fact, be very funny -to- the interns themselves.

(though as tech lead, I always make sure that there are a decent number of jokes flying around directed squarely at me, which probably helps set a baseline of how seriously to take such things - and if in doubt about any particular joke, I just aim it at myself ;)