This is as Karen states ONLY the last night of the cruise. I had heard rumblings that they get a lot of requests for this relaxed code on the last night. So possibly they are trying to accommodate those that expressed this wish.
I suspect in reality not that many people will avail themselves of this casual a code even if it is the last night.
Time will tell and who knows it may be reversed if enough people complain on the other side for a normal "elegant casual" on the last night.
