The Fair Labor Standards Act (FLSA) requires payment of at least the federal minimum wage to covered, nonexempt employees. An employer of a tipped employee is only required to pay $2.13 an hour in direct wages if that amount plus the tips received equals at least the federal minimum wage, the employee retains all tips and the employee customarily and regularly receives more than $30 a month in tips.
Due to these low wages, most if not all people who work as waiters/waitresses rely heavily on tips to acquire the bare necessities of life. Pastor Bell is in an industry, that makes well more than this, and in addition is tax free.
Pastor Bell is using her status as a religious leader, to avoid paying a tip that is necessary due to a federal law. This is using Church, to circumvent state.