My [American] friend is really big into tipping and being "magnanimous" in splitting bills (which usually means I end up paying for other people's drinks or meal NOT cool) and she insisted on making her Spanish friends tip the waiter when they went out for tapas...in Spain.
They were like why and they ended up leaving the equivalent of $1 or something. Waiters in Spain apparently make liveable wages. They also get a restaurant-employee holiday (one month of the year where it's expected restaurants will be closed so employees can go on holiday)
I think being an immigrant myself I assume things are done differently in different countries. In some overseas hotels that cater to tourists, mgmt. specifically asks people NOT to tip, because it is *not* customary in the country. I'm guessing the tips can create issues for management like harder to manage staff or competition/resentment amongst employees.
Even in the states, property management companies often ask residents *not* to tip the maintenance staff (holiday bonuses are fine, just not everyday tipping). 'Cause you know, then the maintenance staff will make the tippers' work orders a priority as opposed to the job they're given to do and residents may circumvent putting requests in with mgmt and just call maintenance staff directly, other residents get pissed off, etc. etc. etc.
Also, there's a tour 'bus' service in DC that circumvents the taxi licensing law by not charging a fare but merely working on tips (for now). I spoke with one of the drivers and he said that what he gets in tips varies widely. One mom with teenaged kids was driven less than a mile (a few metro stops) and she gave him $15. Another guy was driven much farther (cross-town) and fumbled out a few dollars.