There is real value in interfaith services where the rabbi, imam, and minister are each sensitive to the beliefs of others in the room.Jews, Christians, and Muslims together in a joint service.Mh i dont like that.I have no problem with it as long as it's in a Synagogue or Mosque.
In the last two years I've attended an interfaith Thanksgiving service, first in a nearby synagogue and more recently in a nearby mosque. I have no idea where it will be held this year, but the thought of boycotting it should it be held in a church strikes me as preposterous and repugnant - the crucifix/cross in the room is not going to taint my Judaism nor detract from my respect for those Christians eager to participate in such a service.