Q. One who is eating invited by a family on Sukkos and upon arriving sees that their sukkah is not halachically valid or is questionable and he does not wish to eat in such a sukkah, what should he do? Just leave? (For example, they were using sheets as the walls of the sukkah, or other things that make the sukkah halachically problematic).
A. Horav Shlomo Miller’s Shli’a opinion is that there are many likely possibilities and feasible variables, such as the host is friendly and humble and will not be offended if informed of the problematic issue, then one should merit him and his family with the correct Halacha advice.
Otherwise, one may just accept a drink or fruits etc. claiming he is not hungry etc., so he wont insult his host.
The Rov also mentioned that using sheets as sukka walls, although not recommended on the onset, may not necessarily disqualify the sukka, as it depends on the quantity of sway on a common wind and if they lift from the ground three tefochim. (See Mishna Berura 630: 48 and Piskei Teshuvos ibid.: 9).
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a