Three Strikes and you’re out is a commonly used metaphor for a situation where you get 2 warnings then consequences on the 3rd event. Getting a yellow card is a good metaphor for if you only get 1 warning. Any good similar metaphors for alternate numbers of warnings?
It’s not exact but “Fool me once shame on you, fool me twice shame on me” is close.
‘One more time’
And there’s the thing about cats having nine lives, which seems sort of related.
Zero tolerance for no warnings at all. 
Either I have missed “That’s ball three” or the lack of it is evidence that very few Americans have ever seen a need for an idiom for “three warnings and then consequences”.
Yeah, I know, it doesn’t work as well as Three strikes and you’re out … But couldn’t you imagine a drill sergeant getting all up in a recruit’s face and yelling “That’s ball three! One more and I walk all over you!”
Actually, wouldn’t it be “one more and you can get away SCOTT FREE! NO CONSEQUENCES” for Ball 4? 3rd strike and you’re out (in jail); 4th ball and you walk (on base- just what you wanted)
Yeah, that’s why I sad it doesn’t actually work as well. The recipient has to be the pitcher, or the whole out team, and the consequence is having a minor repercussion. And since you’re the batter in the much more used expression it’s no wonder it’s never caught on.
Although I think the relative rarity of “three warnings and a consequence” systems might also be a factor.
Except for the good old “I’m going to count to three AND THEN…”
“51 more mistakes and you’re out of cards, Buster!”
Once is an accident, twice is a coincidence, three times is a pattern.
Another: Toss a coin to choose. If your inner self then says “Let’s go for two out of three”, you’ll know that you’ve already decided.
And: Just wait 'til your father gets home" always worked for me.
In boxing the ref will count to 10 (or is it an 8 count?) before declaring that the person is knocked out.
Well, in a case where you get 3 warnings, you could say, “Four balls and you take a walk!” (as in out the door)