Entering reform temple
My wife’s family from the USA are planning a Bat Mitzvah for their oldest daughter in Israel. They have rented the premises at Beit Shmuel which is the world headquarters for Reform . The family is observant – i.e. American modern chareidim. The kashrus could be reliable because they have external supervision. So the question is not about kashrus.
The question is: are we allowed to go to such a place, taking into consideration that if we refuse to go, the family might be offended?
Thank you very much!
Entering a reform temple may violate the prohibition of Maaris Ayin and Chashad, doing something that appears to be forbidden, such as entering a temple, which looks like you may be joining their services or prayers.
If the institution has a separate social hall, and it is obvious or very well known that entering there may be for an event not connected to the institution, there would be room for leniency.
If you are under pressure to attend from family, you should try to participate in a different way at a different location, for a different part of the simcha. [It is very surprising that a charedi family would rent such a venue for their simcha.]
See Igros Moshe O:C 2:40, 3:25