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For all the marriott I stayed in shanghai 15% is standard operation, where 10% as service fee and 5% for government tax, compeltely normal.
The same goes to in room dining, meal and such in the property. In china, Hong Kong and Macau its almost given that standard 10% to be shown on your receipt as service fee if you go to nicer resturant and / or hotel. Tipping on top of that is strictly optional.