No, just practical. I had no problem paying 2500 for Grab, so why should I dick the dude, I made his life better at no cost to me.
There is no Grab driver alive that wont take a fat fare in cash. They wont ask though. Easiest way to get a long ride. Even better, get the luxury quote and negotiate down depending on the whip. Thus: 3500 baht? Maybe for the Benz, Ill give you 1000 dude for your Toyota, thats not luxury.