Here's my final take on the US situation:
If employees are LEGALLY paid LESS THAN MINIMUM wage, i.e., food/beverage servers, I tip 15% IF the service was adequate. NO more; those prices have increased consistently, so see no reason that my percentage should also.
If employees are paid the LEGAL MINIMUM wage or more, I do not tip. Why should the maid get tipped (I'm PAYING for clean sheets, and paying a lot), when the poor schmuck in the back of the dry cleaners, or anyone making that wage anywhere else, doesn't? No, I'm not cheap; the current whining of "but it's just a few bucks to you, it means a lot to them" or (this one I especially love) "if you can't afford to tip, don't go there" is self-righteous and annoying for the rest of us who have been dragged into this morass of endless tipping for services that we already pay for.