I was in a KTV place in Shanghai several years ago and decided to tip the guy who was doing an excellent job at keeping our little room very well stocked with ice cold beer. I think I gave the guy like 100 RMB. A little later I had to explain to his manager what the money was for...
“Keep the change” has a benefit to both parties - no need to spend time waiting for change to be counted or carrying it round
Colleague of mine left a new generator with his fixer in the Phillipenes when there was a massive hurricane a decade ago. He could the value of it was minimal once the time and money to ship it back to Europe was counted, reality was they needed the generator on site. Could be argued it’s not a bribe/tip/gift.
Giving money directly for services rendered could be a bribe, could be paying him on the side (for more hours for example), could attract tax problems etc.
Driver chased me into the lobby to give me the change.