Once upon a time there was a couple of couples, each with existing children, and each with an expectant mother amongst them. Our two couples decided to go on a
Disney Cruise together - what joyful glee! The only problem that was to be considered was a pesky rule about denying boarding to those 24 weeks along or greater, you see...
Our first mother would be approx 24 1/2 weeks at the time of boarding...alas, she would have been denied her chance to play with the mouse, before someone new arrived at her house. But, our first mother was bold and decided to fib - she told a white lie and said she was not pregnant on her pre-cruise on-line check in, and rolled the dice on her chances. Hang in there, my friend, as our mother starts dances...
She danced right aboard with her big pregnant belly, and never was questioned about the baby or swelling. Once aboard ship, she hid not her tummy - embibing only nonalcoholics which she still said were yummy...Her servers both knew she was expextent with child and no-one ever gave a second thought all the while...
Our second mommy-to-be had a slightly greater problem, for at 26 weeks, she was farther along...her hubby thought of chancing the same style ala mommy one, but was paranoid his quite obviously pregnant mate would be questioned by some...
In addition to this, hubby had a problem, for this mommy did not know she'd be cruising - the trip was a surprise for his darling dear wife, who was beaming and glowing with the expectant new life...
So off to the OB hubby went in a snap and discussed his situation beind his wife's back...the doc understood and expressed no concern about travelling on such a trip being so far along...despite mommy two's history of prior complications, and her high risk situation with this very gestation....
His only advice was to just take it easy - don't let her do too much (and eat ginger if queasy)...so he filled out the fax with one clerical error - it seems mommy two was slightly more slender - for the necessary from for the doctor to write said "22" weeks not "26" right there in black and white...
Now hubby #2 faxed it 14 days before boarding and still kept it a secret, until driving over the bridge to port, when he just had to leak it. Mommy two was just stunned, as you might believe - to be told of her revised date they conceived...but good sport that she was, she just played along - and never was questioned all cruise trip long....
Both mommies had great times (though outside of the rules)...they were an obviously prego-duo (whose hubbies occassionally act fools)...the servers were amused by the two pregnant ladies and a good time was had by all (and that's all I'm saying)...
Whatever you decide, I'm sure you'll have fun...
but you should never think you're the first one,
to approach this problem and have to decide
if the 24 week rule is one you'll abide.
Best of luck...
And my dr would not go against what the airline said was ok, so I figured if I could work on an airplane, I could go on a cruise and sit on a lounge chair. Airplanes don't have the equipment to deliver a baby either...that being said, I'm not advising you to do it, I'm just relaying that it has been done. 
