No, I've never bought myself a gift knowing I'd be unable to pay for a provided service - T, car mechanic, hairdresser, dentist, whatever. I also think a T is the only professional some clients think he/she should understand this (postponing a payment) and frankly, I don't get why.
I'm not judging your behavior- and I've seen others act this way- I just don't understand what makes the Ts so "special"? Do you, by doing so, make the RS more personal/friend-like?