Primarily because Americans are simply so accustomed to it….so we do it even when we don’t need to.
At *most* all-inclusive resorts, the ‘tips’ are included in your package prices so you don’t NEED to shove a dollar at the bartender/waitress/porter. And at some of those resorts, employees are not supposed to accept tips, so it’s important to know before you go.
So even though it’s NOT expected, does it get you better service? Eh…the jury is still out on that – the wait-staff at all-inclusive resorts really cannot afford to have any unhappy guests, so they certainly won’t ignore the non-tippers, and I’ve personally observed them treating both tippers and non-tippers with equal care and service, so my advice is that you should only tip if you really, really want to reward someone, but be sure you won’t jeopardize their job if you do.
That said, we’ve got a terrific blog post all about tipping at all inclusive resorts, we’d love to see YOUR opinion in the comments!