In the sefer Aleinu L’Shabeiach, Rav Yitzchok Zilberstein describes a question that he was once asked by a baal teshuvah in progress. The man, who had once been completely irreligious, had begun wearing a yarmulke and keeping some mitzvos, but he was unable to stop going to soccer games, even on Shabbos. The man wanted to know if he should remove his yarmulke when he went to the stadium on Shabbos in order to avoid causing a chillul Hashem.
Rav Zilberstein went to see his father-in-law, Rav Elyashiv, and presented the sh’eilah to him. Rav Elyashiv’s advice was for the man to wear a cap. There is a Gemara that addresses this issue: “If a person’s yetzer hara overpowers him, he should go to a place where no one knows him, wrap himself in black garments, and do as his heart desires—but let him not make a chillul Hashem.”
A sin in private is not nearly as serious as chillul Hashem done in public. The Gemara in Kiddushin (40a) likewise states, “It is better for a person to commit a transgression in private and not desecrate the Divine Name in public.”
Reproduced from Living Kiddush Hashem by Rabbi Shraga Freedman with permission of the copyright holders, ArtScroll/Mesorah Publications, Ltd.