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Actually I disagree. The OP didn't know, okay, "gasp" heaven forbid she made a mistake about the "expensive" cake. She wanted a nice celebration for the child, without spoiling the surprise birthday cake, if it would have sat on the table. Her only request was to hold the cake behind the scenes. Afterall, 1900 Park fare did, and solved the issue and everyone was happy. Believe in me you want happy customers for repeat business. If customers aren't happy, it's a little known thing called word of mouth. It already looks like CM is getting poor ratings but alot of posters here in this forum. Most restaurants would accomodate a paying customer. I didn't think her request was all that difficult to accomodate. Afterall Disney is all for CELEBRATIONS. She really did get less than stellar service from the manager and waitress. Usually Disney is very accomodating.
Why is the surprise diminished if it is given to the child when they sit down to dinner? Why was having an elaborate presentation at dessert so all-important?
This is what I mean by being flexible. Life isn't perfect-- hiccups happen. You just make the best of it and move on. Especially on vacation! If having a birthday party go EXACTLY as planned is really critical, then the planning needs to be made ahead of time.
You said it yourself-- the OP made a mistake. No need to blame the restaurant for it.