All those saying that Rav Moshe Z”l didn’t limit his Heter to extenuating circumstances, please see the letter I typed from him on the previous page. Seems many here missed it.
There is a story told (like all stories, if it confirms your position you’ll believe it, if not, not) that R Moshes daughter in law once gave him something Milchig to eat, and afterward realized that it wasn’t Chalav Yisrael, and told him. R Moshe immediately went to throw it up.
(I heard this from a prominent Rov, who heard it from a Yid who lived in R Moshes building.)