I found this idea of using a vase as a card box. Something like below. I like it since I'm not so crafty when it comes to involving tools.
My only concern is if this will be safe. I heard about party crashers stealing cards, etc. Both the ceremony and reception are at my church - the neighborhood is good and safe, but the church door is open so anyone can come in (although I haven't really seen total strangers in the church). I'm also trying to use a bit shallow vase (6 inch square vase), shallow enough that someone can just grab a chunk. What can I do to make it "safer"? Any ideas...?