Speaking for myself, I really don't want to sell you too much cake, because nobody likes to hear from a bride that there was an entire tier left over. If the server cuts the cake a different size than the "standard" though, that's exactly what will happen. The standard size for a piece of wedding cake is supposed to be 1" x2" x the height of the cake, like the piece on the right, but it's often cut much thinner and a little longer to cover the plate better, like the piece on the left. If it's cut that way it will give you 25% more servings than what I estimate. What happens to the extra cake, then? Is it saved for you, or does the staff help themselves to it?
I've done cake for a few functions recently where the cake pieces were cut way too small, and they ended up having a lot left over. Seeing that I really have no desire to eat cake at the end of the day, I just told the staff to take it home. If you're a paying bride, though, that probably isn't what you want to have happen to your extra cake, and you probably don't want a lot of leftovers to begin with.
On the other hand, you also don't want to run out of cake, which is one reason that the pieces might be cut smaller. If the person who's cutting the cake is faced with a small three-tiered cake to serve to 200 guests, the pieces aren't going to be very big, and you'll probably still run out. You need to be realistic when buying the cake to get enough for your guests, and not try to reduce your expenses by ordering too little cake.
I asked Anne Roy, the Sales Director for The Boathouse at Sunday Park, for her insight on the topic of staff eating the cake, the cake being too big or small, etc. She had some interesting points to make, so I'm going to reprint her email for you all here:
At the Boathouse(s) we do not take the cake out of the dining room. We cut and serve it in front of the guests. Then we wrap the leftover cake (uncut) and hope the party takes it with them. When there is extra cake, we always leave plated slices on the cake table to encourage guests to have another piece. If there is leftover plated cake at the end of the reception, we do let the staff have the cake instead of just throwing it out.
I have cut hundreds of wedding cakes in the past 11 years. There have been times when I have been cutting the cake and had to start making the cake slices smaller and smaller as it became obvious that we weren't going to have enough for all of the guests.
Some of your skimpy slices could also be due to the cake cutting staff not being experienced at cutting cake. That is the single most daunting moment in the life of many Banquet staff. I think that is why the cake is often taken out of the dining room. Cutting the cake can be really messy for people who don't know how to do it. Especially cakes with fondant, melting buttercream, insufficient supports, or those that are still frozen.
I have never heard of staff eating cake before they serve it to the guests. If this happens, I suspect it happens at locations without a professional serving staff - the type of caterers that rely on untrained temps, or unsupervised part-timers.
The serving staff is unfortunately - and usually unfairly - blamed for many things at a reception. The servers work very, very hard. Many event shifts can be 9 hours long. Yet, the staff are still smiling at the guests at the end of the party. I choose to believe these cake-eaters are unusual and this is a very rare occurrence. And I say with absolute confidence that this does not happen at the Boathouse.
I think that it's important to note Anne's comments about the professionalism of the serving staff, and also the part about cakes that aren't built properly being the ones that are difficult to cut! Thanks for the insight, and for all you brides, keep in mind that, once again, this is another example of why it's important to hire professionals who know what they're doing. By hiring experienced pros you'll make sure that your cake will serve the number of guests it's intended to, and that the staff won't be having a tea party with your cake while your guests are waiting to be served!
Visit Anne's Blog at http://theboathouseatsundaypark.com/blog