Also, I couldn't edit my comment, but I meant to say, IANAL/IANAA, but my understanding is that the IRS reserves the right to assume if wait staff document the

Also, I couldn't edit my comment, but I meant to say, IANAL/IANAA, but my understanding is that the IRS reserves the right to assume if wait staff document they made less than 18% of sales in tips, they are pocketing cash without claiming the income. It is impossible to prove a negative, that they didn't receive cash tips.