Originally Posted by Numbskull
A Christian attending a Jewish service dishonors himself by wearing a yamulke. Likewise, a Muslim woman attending a Catholic service would still need to wear a burka.
I would agree with this if either of the following were true:
1. A yamulke had a specific religious significance (as does, say, a cross).
or
2. Christianity requires you to pray with a bare head
and you intended to pray at the Jewish service.
Neither, however, is the case. A yamulke has no particular meaning at all. It is a hat, nothing more. Any hat, from a fedora to a baseball cap, will serve the same purpose -- showing respect for the synagogue by following its tradition of not being there with an uncovered head.
Christianity does not require you to pray uncovered. In fact, at many outdoor ceremonies hats are worn by men. Moreover, as pointed out earlier, many church authorities wear hats, often identical to yamulkes, during services. The idea of removing your hat upon entering a church is not a religious requirement but a Western civil tradition -- you do the same in any public building from a courthouse to a restaurant.