[WalterBright]

A few cases come to mind.

1. The government froze wages in WW2, and companies got around that by offering free health insurance.

2. Unions often got the government to force workers to join the union, because otherwise workers would undercut the union.

3. There were numerous attempts to fix wages of black laborers artificially low after the Civil War, they would constantly fall apart because individual farmers would pay more under the table to attract better workers. See "The Strange Career of Jim Crow".

4. Government "price supports" are there because of the consistent failure of farmers to voluntarily comply with price fixing agreements.

[WalterBright]

I forgot to add - anti-dumping, unfair competition, and predatory pricing laws. Those are just a way to use regulation to fix prices because voluntary price fixing fails.