You are probably right that it doesn't happen, but it's not
as senseless and ridiculous as you think.
For openers, if we think back to the days of handicapped post position assignment, the weaker teams were usually in posts 1-2-3 whle the tough guys were in 5-6-7. If post 1 scored 4 points and then lost, he would be "behind enemy lines", so to speak, and to get any further he would have to do it by exclusively facing the very best in the game. But if he had only scored 1 point first time, he would be in a position to win the game without facing even one of the top players or teams within his group.
I think it is possible for similar scenarios to occur today, such that every serious 'jai-alai analyst' (assuming they existed) might reach the identical conclusion that in a specific game, owing to the particular head-to-head matchups, it might be most advantageous for post 2 to win just 1 point (or 3, whatever) the first time up. And yes, even the players might know that.
To give an example, it is better for your win chances to have exactly 3 points first time up than it is to have exactly 4. But when you have 3 points, you don't know if you will get to 4 and stop, or keep going and get 5 or more. However, if you knew that for the 5th point, you would be serving to Arregui - who ALWAYS shreds your serve - then you would be better to to stop at 3 and probably not even have to face him now or even next time up. This is part of what would be considered 'game theory'.
So my point is ... that whether we are aware of them or not, from time to time certain situations arise where it is OBJECTIVELY better to lose a point. And even though it is unlikely that anyone is acting on that, it still is not a 'senseless and ridiculous' idea. Particularly since it could lead to more wins.