Hypothetical Scenario:
1. Your gambling with somebody who isn't your close friend or a regular opponent.
2. Your winning the session considerably but you aren't stealing.
3. You want the guy to quit so you can leave with the cash.
4. Your opponent insists that he deserves a spot and makes a good point about how he only won X amount of games in the past X sets.
How do you turn down the request without being a total a-hole and having them throw a tantrum before leaving?
There are no guarantees when gambling and anyone can quit at any time, which many people on here will attest to, and many have expressed those feelings strongly when this topic has come up in previous posts. However, historically it is generally considered good gambling etiquette, even among strangers, that whoever is winning, unless they have set a time frame on the session they have verbalized to their opponent at the start, should continue playing (within reason) as long as their opponent wants to, as long as the game, the amount $ they are playing for, and spot (or no spot) remains the same.
If you are playing even and you are up at least a few sets or more, and the loser is requesting a spot or to change the amount of the wager (more or less), you have the option of accepting his request, negotiating a smaller spot, or rejecting his request and informing him that he can quit whenever he desires. He may not like it, but that's the way it is. You are absolutely under no obligation to have to change the terms of the original bet.
Your 3rd statement that you want the guy to quit so you can leave with the cash, comes across as nitty to me - sorry if you don't like my honest opinion. The best way to get him to quit soon and leave with the cash is to refuse to change the bet and continue to beat him as badly as you can - eventually he will give up. If you are beating an opponent and you feel you can continue to do so, your mindset should be to break him of everything he's got!