At first this didn’t make much sense to me as the incentive to protect the official is still there — you’re getting something you want, so why ruin it? But read

At first this didn’t make much sense to me as the incentive to protect the official is still there — you’re getting something you want, so why ruin it? But reading the abstract it’s referring to a specific kind of a bribe — where you have to pay to get something you’re entitled to anyway (under a threat of unnecessary delays for example). I doubt it would have much of an effect on another kind of bribe where there’s discretion and you’re getting something you might not otherwise get at all (as is the case in the article).