At this point I think the issue is less of "witnessing" or
prostelyzing (sp? can't find it in my dictionary) and more an
issue for Miss Manners. I was brought up *never* to discuss
religion with strangers. I consider people who want to foster
their ideas and beliefs upon me to be rude and ill-mannered. Jay
was being more than gracious by being polite and considerate.
The lunch companions were being rude when Jay made it clear
that he was uncomfortable with the topics.

Of course there are times when it's perfectly permissable to
just say "You are ruining my delightful day with my wife, and
ruining my lunch" then go to another table.