To answer my own question, while there is an "optional" formal night; the dress codes for this night ranged everywhere from suits, beautiful dresses, high heels, jackets and ties, to only jackets, to t-shirts and shorts, sandals, etc.
So, if you choose to dress formally it is your prerogative, but hardly a requirement. The dress code was relatively relaxed as I suspected.
It seems a lot of the mainstream cruiselines have less formal attire on formal night than before. My last three cruises I saw a few tux's on men, some suits, but more shirt and tie, or sports coat with no tie.
Freedom of the Seas Dec 11
Allure of the Seas: Jan 11
Voyager of the Seas: May 09
Splendour of the Seas: May 07
Explorer of the Seas: Jan 04
Majesty of the Seas Jan 99