R' Tsvi Heber of the Kashruth Council of Canada writes:
Is it permitted to order whole fruit[34] or drink water in a non-kosher restaurant? If not, can one enter a non-kosher restaurant to use their restroom or sit down at a meeting without eating anything?
[...]
Rav Moshe Feinstein zt"l[41] was asked if it is permitted to eat kosher food in a non-kosher dairy restaurant. [Igros Moshe O.C. 2:40; see the final paragraph in the original Hebrew or translation.] His unequivocal response was to [usually] forbid "going into the restaurant to eat even food that is known to be kosher". Some have understood that Rav Moshe intended to prohibit even going into a non-kosher restaurant, perhaps even to use the restroom.[42] [...]
A careful reading of Rav Moshe's response indicates that he did not forbid entering into the restaurant. Rather, he is addressing a scenario where someone is ordering food from the non-kosher establishment and eating it. In that case, the onlooker would perceive that he was being served [non-kosher] food by the restaurant. It is not clear that Rav Moshe would forbid entering the restaurant or even sitting down to eat one's own food or even pre-packaged food that is served by the restaurant since there is a clear differentiation between your food and the regular non-kosher food. Furthermore, pre-packaged kosher meals have become a popular item in the kosher catering industry. Perhaps this new phenomenon alleviates to concern of maris ayin since it is now well-known that this option is available.
In an article entitled "Keeping Kosher – Eating Out", a disciple of R' Yehuda Herzl Henkin named R' David Sperling adds:
I heard from Rav Y.H. Henkin, shlitah, that even according to the opinion of Rav Feinstein, one could enter a non-kosher restaurant to use the bathroom.
Hmmm. Rav Feinstein told the hungry querent to normally not even enter non-kosher restaurants. Personally, I suspect that the querent wasn't very religious; maybe Rav Feinstein said this in order to keep the querent away from temptation.
R' Heber is right. Some rabbis seem to understand the responsum's last sentence to be telling the whole world "One normally should not enter a non-kosher restaurant". For example:
- R' Yirmiyohu Kaganoff. "Marit Ayin". Sub voce: "Rav Moshe Feinstein rules".
- R' Mordechai Frankel. "Insights from the Institute". Kashrus Kurrents. Summer 2009. Sub voce: "It would seem that".
How could these rabbis take a responsum written to an individual and generalize the answer to apply to the whole world? Might they be doing so because they feel it's less risky to be strict? Might it be less effort for them to be strict? Might there be some other reason?
As always, CYLOR.
@msh210so I can reopen.