The second part of his study involved an offended hospital challenging Rosenhan to send pseudopatients to its facility, whom its staff would then detect. Rosenhan agreed and in the following weeks out of 193 new patients the staff identified 41 as potential pseudopatients, with 19 of these receiving suspicion from at least 1 psychiatrist and 1 other staff member. In fact Rosenhan had sent no one to the hospital.
Conducting an important scientific experiment, teaching a painful lesson to those who challenge your authority, and showing your good sense of humor. Without any work whatsoever. It must have felt good.
I haven't seen any links to this on Lesswrong yet, and I just discovered it myself. It's extremely interesting, and has a lot of implications for how the way that people perceive and think of others are largely determined by their environmental context. It's also a fairly good indict of presumably common psychiatric practices, although it's also presumably outdated by now. Maybe some of you are already familiar with it, but I thought I'd mention it and post a link for those of you who aren't.
There's probably newer research on this, but I don't have time to investigate it at the moment.
http://en.wikipedia.org/wiki/Rosenhan_experiment