Who is to decide what Halachos are applicable or not!
A Rebbi of mine told me that he was learning Hilchos Pesach before the Yom Tov. He was doing the part where the Mechaber discusses what to do if you forget the Affikomen.
He thought that this Halchah is irrelevant because how can you forget the Affikomen in a house full of kids! So he skipped it.
Anyways, two night before Pesach his wife gives birth to twins. He was in the hospital the whole night with her.
The next whole day an night he is busy doing all the last minute things himself, arranging places for all his kids to stay, last minute cleaning, Bedikas Chametz etc so he had no sleep again. Erev Pesach he was again running around.
He sits down to the seder all by himself. Sure enough after two nights of no sleep, and the busiest 48 hours of his life, he finishes Shulchan Orech and Bentches, forgetting to eat the Affikomen.
With his eyelids weighing as much as a loaded Airbus A380 (or 747 for the old folks) he drags his body to the shelf to get a Mishna Berurah to see the Halachah.
That was his lesson to us never to skip over any Halachos claiming they are irrelevant.