Normal camera bag, be obvious. Make it bold, so no one pretends to just wanter off with it.
Place it at front of church out of view, but accessable from a side aisle during ceremony, and have a tasteful leather fanny pack to swap spare one lens in/out of and stash films to draw from/ as they are exposed.
At publc gardens, set it just out of the frame, but beside the party you are posing.
At reception, set beside the dj, etc. If you shoot weddings you will develop a rapport with the other 'trade pro's' and you will find you are busy at different times and can look out for each other.