You may end up with left overs but that isn't nearly as bad as not having enough. I know I was at a wedding where the favors were at our seats and somone still walked off with mine. Not that I cared but in that case I'm not going to think the bride goofed but if they are just on a table guests might think you didn't plan well if there weren't enough.
Re: Favor Question
With All the Trimmings