Chile specific - Currency question

[ChuckinSC]

We're on a cruise early next month starting in Santiago (San Antonio) with several port stops along the Chilean coast.  All of our tour excursions are booked with the cruise line (Celebrity).  Will tipping tour guides using U.S. dollars be acceptable or should I arrange for pesos beforehand?  One or two other places - the shuttle bus driver, porters at the airport and at the pier?  Will they be okay with American dollars or only Chilean currency?  Advice is needed.  Thanks.

[Lunenburg]

They are used to being given dollars. Tipping is less common down here. On our recent trips in Brazil and Argentina - both land tours and cruise excursions, only the N. Americans seemed to give tips, none from locals and even the Europeans rarely gave tips. 

I have not seen anyone tip a shuttle bus driver or the porters at the cruise terminals here but maybe some people do.