I just spend a few minute refining my thoughts on tipping outside the US : I would say it has to do with a relationship with money and the power emanating from it.
Tipping is not expected in most places; and doing it anyway clearly signal that you have some disposable wealth. You can afford to pay even more than the agreed upon price.
There is some “bling” and nouveau-riche aspect to it that will leave people a weird feeling.
For instance : Are you trying to bribe them? Do you think they are too poor to function without your patronage? Are the price/money here just a joke to you?
And then, it become your edge. You are the guy or gal that pay extra. As opposed to be the funny/sexy/mysterious/resourceful person. AKA : El gringo, l’américain, l’americano. ( I’m one of you now, so I can say it :p )
Being seen that way might be a way to attract the wrong kind of company.
I don’t know about casino and hazard games, my passion always has been the dives and the likes.
But you do say something important about establishing contact first.
That’s a great difference in my book.
I still maintain that waving money around FIRST won’t help on the long run. Establishing rapport and discretely paying extra might, sometime, with some people. But being nice and aware of your environment might do just the same.