Are you seeking MY approval, Ryemo?
Certainly nothing illegal about what you describe. I would even say nothing "wrong" with it, as per my own guidelines. BUT, it's not the way I operate. I scout dealer that I want to play with (penetration). If something changes and the penetration changes, I move on. There are plenty more opportunities. I just have no interest in 'training' the dealer.
The problem for me with the tipping for better penetration is not even necessarily THAT level but what comes next. Once you become one of the frequent tippers, the relationship changes. The dealer starts wanting you to win, to do well, because that means more tips. Some dealers will take that 'hoping' you win a little further. All of the sudden there is a mispay, or your 18 pushes against the dealer 19. Once the dealer decides it is better for him/her (but mostly him) if you are winning, it really is not that far down that slippery slope.
I am not judging any player that does anything, that I chose not to do....well up until actual cheating or collusion. I just have the way I like to win. The house sets the rules and conditions and I come in and play by them and win. That makes me feel good.