I think that most pianists do not observe it strictly because it is extremely difficult. Not so difficult to play in tempo....but difficult to be expressive
while playing in tempo. Even after playing so much Bach, so that our hands are independent of each other, it is extremely counterintuitive to most of us to let one hand be free of the other in this sense, especially in certain types of music, like the more lyrical pieces and episodes of Chopin. So we do what is easier: we are expressive via the unwritten ritardando and accelerando - this 'all over the place' rubato that is common in most Chopin interpretations (including mine, much to my disappointment).
So, since it is difficult, I think for many years, professional pianists have justified this non-Chopin type of rubato in Chopin by saying that to play Chopin in strict tempo must be mechanical, and non-musical. But I don't believe that is the case.
Sorry for going OT, Monica...especially seeing as how I think we have argued about this before.
I will add my voice to those who think you should play what you are most comfortable with, at the competition. As Alfie says, it's a no-brainer.