From their classic textbook, Universal Economics:

Not only are violations of ethics more likely to prevent successful market activities but they are arguably more powerful in the economic market than in the markets of political and social exchange. Ask whether a seller/supplier or a politician tends to make more reliable promises. Which will suffer most, and most quickly, if caught being dishonest or evasive?

This is obviously a rhetorical question–to ask it is to answer it. Yes I’m happy I’ve assigned this supplementary text in Intermediate Microeconomics!