It's easy to point fingers, but I would bet any of us would buckle under the pressure of free pizza...
"To see whether a small incentive could influence a decision about privacy, researchers offered one group of students a free pizza — as long as they disclosed three friends’ email addresses.
An overwhelming majority of the students chose pizza over protecting their friends’ privacy. Differences in gender or their stated personal sensitivities to privacy did not seem to have any effect on the choice."