I have Ismaili neighbors and when a relative of theirs had died we asked if we could come to their mosque for the namaz, majlis, whatever you do for it but they told us Non-Ismailis cannot go to the mosque. Why is that?
well, i haven't heard any farman of our imam about not allowing non-ismailis into jamat khana but i guess the reason might be that we say the names of not just hazrat muhammad (S.A.W) and hazrat ali (A.S) but also our imams (A.S) during our D'ua (namaz).. i don't think any non-ismaili would want to say that they believe in our imams.. so i guess that's he main reason.. other reasons include trouble-making ppl especially guys.. but i guess u can visit jamat khana at other times.. i would personally like to take non-ismailis on a visit to any of our jamat khanas..