Enforcement
Often when an employee is working under-the-table, both the employer and employee have agreed on this method of payment/employment. Frequently the employer is running an unreported cash-based business. These methods make detection by authorities time-consuming and difficult. Most small-scale operations take place without any real enforcement effort. Lawn-mowing is a good example of a cash-based business that is frequently unreported.
In the United States, authorities have focused enforcement resources on larger scale operations like illegal immigrants who are employed by large companies. Discovery and enforcement of smaller-scaled unreported employment is typically through a secondary indiscretion like fraud, tax irregularities, and unrelated or partially related civil/criminal violations of the employer or employee.
Although the Federal Government may arrest, prosecute, and imprison an individual for engaging in commerce without the State's approval, the high cost of such enforcement is prohibitive and is usually reserved for the most egregious cases.
Read more about this topic: Unreported Employment