A NY District Attorney argued mandatory tipping was not legal after a man was arrested for not leaving a full 18% tip that was stated as being mandatory (he tipped 10% due to bad food). The courts agreed and the charges were dropped.

http://www.nytimes.com/2004/09/15/nyregion/15tipper.html?_r=1&oref=slogin

"...The reason restaurants want to replace tips with service charges is so customers will give the business money that they used to give the employees. Remember tips are the sole property of the tipped employee, that means that moneys received as tips can't be used by the business. On the other hand, moneys received as service charges are the business's property and as such the business can do what ever they want to do with those moneys.... Replacing tips with service charges actually means that customers will be giving the business money instead of the employees....service charges are the business property not tip income for the employees. What will actually happen is that the money that used to be given to the employees will become by law the employer's property. What this means to workers is that the tips that they used to receive from customers and which were protected by law as their sole property will become property of their employer. What this also means is that a customer's right to determine whether a tip is given, the amount and who will be the recipient of his tips will be replaced by an automatic charge which denies customers their right to determine such matters and which results in the business fraudulently reaping the financial rewards of the tip that would have gone to an employee of the customer's choosing.

Most customers who pay these service charges think they are the same thing as a tip. In fact, many restaurants openly suggest that the service charge is in lieu of a tip. What is in lieu. Alternately, alternatively, by choice, by preference, first, in lieu, in preference, instead. Business want customers ,to instead of tipping their employees,give the business additional income.

3. Is it legal.
Customers are being led to believe that a service charge may be paid in place of a tip, however no distinction is being made that the service charge is not the same as a tip. Many customers are paying these service charges with a misguided impression that a service charge is the same as a tip when clearly there are distinct differences. Customers, in fact, are paying service charges that they think are money intended as tips not knowing that the money is legally the business's...such practices are fraud on the consumer and not only fraud but intentional fraud. Businesses have every right and ability to charge more for their services if additional income is needed. Instead of charging more for their services many businesses are intentionally substituting service charges for tips in an effort to defraud money out of the public."

Quote unquote.

If you're living life on the edge, you've got too much room.