Don't bet on any pool player!
I was recently told by someone I know, and trust, who is extremely well informed, about MASSIVE dumping and collusion on the Eurotour and even the WPC. If I wasn't disillusioned before, I am now. I'm NEVER betting on any pool game I am not playing in.
As far as calcuttas go: You guys are treating it like it's some sort of labour contract! I get it, it's not ethical not to give your best, I certainly wouldn't concede frames if someone was betting on me, but that's not the point, is it? Are you expecting the pool player to "work for you", to answer to you as an employee, because you bet on them? I'm sorry, but you are going to be very disappointed (and possibly poor).
I wanted to become a psychologist once upon a time. I learned just enough to realize that most people are pretty boring, predictable, selfish and they lie A LOT. You want to be depressed? Read 1000 personality questionnaires! First you realize that everyone is lying. Then you realize that they are too stupid to realize that the questionaires are explicitly made to detect those lies.

Then the third strike: You realize that you are probably just as bad as them, even worse because you have a superiority complex as well as those other traits.
When someone is dependable and act accordding to principles, people call them boring, yet those are the exceptional ones. Most people act according to their animal instincts, then rationalize it afterwards. But those stories are oh so beautiful and logical. They bring tears to ones eyes

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If you must bet on a pool player or indeed any "athlete" in a individual sport with few monetary rewards, always ask yourself:
"What would a greedy, short sighted idiot with no other marketable skills or prospects do in this situation?" The situation being one where it is close to impossible to detect cheating, no proper way to make any kind of sanction that sticks and highly lucrative to cheat. If they are in a slightly different situation where the outcome is more or less indifferent to the player, then expect them to act indifferently.
I'd place the bet in one of those directions, however, you need them to be unaware that you placed the bet as well, that's where it gets tricky.
Good luck.