I wanted to thank LisaP for the insight on the special needs issue. Everyone really does need to decide if you want the cruiseline to be aware of any special needs before answering the question your agents are trained to ask about such needs. If you answer "yes" to the question "Do you have any special needs there may well be a form required by the cruiseline. Depending on the need, you may be required a medical okay and letter from your doctor. If you have no need of special diet or assistance from the ship staff you may well save yourself time and trouble by answering either "no" or "that's none of the cruiselines business".
I have a number of clients who opt for the latter answers. If your need is life threatening like some food alergies, it's a VERY good idea to notify even with the add'l forms and hoops some lines make you jump through. Just be aware, if you notify, it's their ship and policies. You may be required to elaborate and accommodate their add'l requests for information, abide by thier restrictions, etc. in order to cruise.