When I checked into the Hilton, I took a piece of candy from the dish at the registration desk. I was surprised to see it read: "The name of the LORD is a strong tower: the righteous runneth into it, and it is safe. Proverbs 18:10." I wasn't expecting such a message on my mint from the front desk of a major convention hotel.
There were several more dishes, all filled with candy of similar sentiments, and all branded by Scripture Candy: "Reaching the World One Piece at a Time!" Later I learned that they were placed there for the Catholic convention that was in the hotel, but I had to ask to find that out. Nowhere was there any signage or indication of the targeted audience.
All conventions have special touches that appeal to their attendees and I applaud the organizers and hotel for paying attention to such details. But if you are doing something that is out of the mainstream, remember the non-participants who will encounter it. A word of context can go a long way in making your message subtle instead of surprising.