Here is a general guide to tipping in Mexico. It is customary to tip at the Palladium but not mandatory. If you are going to exchange currency then it is best to use pesos. Try and bring small bills (20s & 50s). If you plan to use US then bring lots of ones & fives. No foreign coins are useable.
Tipping in Mexico
Note the housekeeper does not refill the fridge. There is another person who does that. If you need something in the fridge leave a note with $1 or 20 pesos.