To be fair, I think the Colonial Brits and other Europeans were galavanting around the globe handing out gratuities long before Squanto showed us Yanks how to feed ourselves in exchange for a flintlock. In some places it took hold as 'tipping' where others it evolved into something along the lines of Egyptian baksheesh (more bribe than tip). Other places get the tip out of you one way or another (by altering your service according to what you paid). Our tipping culture in the US didn't begin in force until the late 19th century, when the nouveau riche decided to be more cosmopolitan and mimic the European custom at the time.

The thing about culture (or custom) is that it mixes and spreads, and nobody owns it. The same romantic notion that travelers shouldn't upset 'quaint' local customs ("look dear, it's so nice, they still live in grass houses!") can also lead to preservation of disease and high infant mortality. There are far more dangerous things in this world than misplaced American generosity, however naive and unnecessary it may be.