I just reread this whole thread, and it seems that I've said a
lot without really answering the original question! (Sorry....)
To me, fixing implies taking an action to ensure that a desired
result occurs, or at least one of a desired group of results.
Therefore, it's a fix if certain players intentionally lose points
so that certain outcomes will result.
As for intentionally losing a point when one's opponent is at
game point, to lock up place boleto, in my opinion that's cheating,
but not a fix, because it's not done with the intention of forcing
a pre-determined outcome. Fixing implies a pre-determined outcome
on which the insiders can bet.
