Yes, especially when the prices are all arbitrarily set in the first place. Another thing is that a lot of people in here that live in the US complain about the way things "should" work on Cozumel, as if the rules we are used to should apply to them. Their country, their rules, such as they are.
Any time an economically disadvantaged region becomes an international tourist destination there will be metaphorical osmotic pressure for money to move from one side of the economic membrane to the other; it is unavoidable. You go there, you deal with it in whichever way you choose. I choose to be reasonably diligent against scamming but to not sweat the small stuff. YMMV
Seems to me that a lot of Americans like to travel to foreign countries, as long as they are Americanized. Want American? Vacation in America.