It is both a prerogative and an implicit obligation for the socially prominent to be particular about."

"I did not want to be running any vehicle where my implicit obligation was to earn the highest return I could every year," Buffett says.

Mr. Rich had an implicit obligation, Mr. Papp said, to give the new "Serious Money" the same positive commentary as the old.

And if the television airways are technically free to the networks, isn't there some implicit obligation to ensure television programming of all sorts (not just lowbrow) and for all ages?

Both POS and PPCV are types of social exchange and therefore involve implicit obligations, rather than economic exchange, which involve explicit obligations (Blau, 1964; Emerson, 1972).