Even those who hold by Rav Moshe’s shitta, Rav Moshe paskens that a Baal Nefesh should only eat Cholov Yisroel. He doesn’t pasken that a Baal Nefesh should only eat CY when home. So a Baal Nefesh should only eat CY anywhere, even when a guest, according to Rav Moshe.
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