What kind of place card holders are they? what do they look like? Do they look like they have been purchased by you, or property of the reception place?
Sorry for the questions, but its a little hard to say without further details
I'm having wine cork holders which I made myself from the corks that my FH and I have drunk over the years. I am more than happy if guests want to take them home as they basically cost me nothing, apart from the blood, sweat and tears making the bloody things!
Its a hard one, because, you dont want to say not to take them right? and if you do have dinner parties all of the time, they would be a nice reminder of your wedding. I think that most people think that weddings arent a free for all, and im hoping that most people would ask before they take something?