Rented Vase/Urn for Centerpiece?

Sorry for posting this again, but so far no one has had any ideas about this one:

My florist suggested a silver urn for my low centerpieces. This would work well with the decor of the room. However, the urns would be rented, so guests would not be able to take them home. Has anyone rented the vases or urns for their centerpieces? (Or have you been to a wedding where this was done?) If so, how did you let your guests know (in a tactful way) that they were welcome to take the CP, but not the urn? Did you have other containers available for guests to transport the flowers home in? My florist said the flowers would be in floral foam, which would then be placed in the urn, so I'm thinking this could be drippy to transport.

Thanks for your input!

My cousin had high CPs at her weddding... it was in 2 parts.. the bottom part was a tall vase and the top was the flowers in a short vase. The florist came in before the end of the reception and took all the flowers off of the tall vase.. he took all the flowers out and made little bo-k's for all the women as they left...