That is the guide as to what to wear, to hopefully avoid confusion.
From P&O what to wear...'' The dress code is applicable to all passengers of 18 years and over and we request that on Formal or Semi-Formal evenings children wear, as a minimum, Smart Casual dress, however on these occasions dark denim is not permitted. In the evenings all restaurants and bars comply with the dress code of the evening, with the exception of the buffet.''
The trouble is they don't!!