I do what others do out of respect for them and their tradition. Someone else's religious house or venue is not the place to make a statement that I don't follow their religion. My family is Roman Catholic, I am the only one who is not. Given that, I don't have much choice except to attend their events. At funerals, christenings and weddings I do what they do, with the exception of genuflecting and the sign of the cross. Though I will make a reverent acknowledgement when I enter the church. It is after all, the house of someone's God, and won't kill me to do so. Just as I'd expect them to be reverent in my temple and at least give a cursory namaskar to the deities.