I think Norm was referring to the cultural differences, rather than the fashion ones...IMHO
First off, most ships are NOT american, US, domestic...etc. They are registered and based in a foreign country. Lets say British, The Brits have a way of upholding traditions, and know how and when it is appropriate to skew from the 'Upheld' to the acceptable.
Although it does say shorts aren't permitted, this is more or less to make a point to us lazy americans about the ambiance the line wants to maintain. The difference is shorts to us are 25.00 vacation wear, in Bermuda, dress or tux shorts are 125.00 to 150.00 wool with a satin strip down the sides. and they have a matching jacket to go with them.
I actually went to SMITHS in Bermuda and bought and wore a pair of these shorts on a cruise years ago. It was a lot of fun, keeping in tradition with the culture, and really not in defiance of the dress code. I however have never worn them other than in Bermuda. I wear what we in this country have come to know as a traditional tuxedo or a dinner jacket .
I however see nothing wrong with wearing an upscale pantsuit. It however is considered casual or informal at most by cruise dress codes.
Only because we as americans tend to be a more casual culture than the rest of the world.
by the way, IMHO...I don't think a grass skirt would be appropriate formal wear on a Hawaiian cruise