Not sure if this would fall under etiquette or not, but this is where I'm starting...
Centerpieces....how to give them to guests if they want them? Just make a general announcement that "hey, if you like something, take it home", or do a "drawing"? If someone is interested in taking one home, they can put their name in a hat or something like that? Personally, I'm ok with taking them all home and reusing the containers for future seasons (autumn theme, which is my favorite time of year), but I also know some people may like them as well. And not everyone will be interested, so I don't want to do one of those "the person with the gold star under their plate gets the centerpiece".