Just because some folks do not dress FORMAL on a FORMAL night does say it is OK.
Some cruise lines enfore the dress code more than others.
This topic has been posted 100's of times. I think that folks start a thread on this subject is to get the "approval" of other folks on the board. It does not chnage the suggested dress from FORMAL to somehting less.
If you do not care to follow the FORMAL night(s) suggested code, go eat on the mess deck on the fantail.