All,
Thanks for the information -- I was initially concerned as I'd heard rumours of airlines like BA being picky with dress code, but from your responses it looks like SQ is quite happy with whatever their fee-paying F class passengers wear.
On a slightly unrelated note, who makes up the usual clientele in F class on SQ? I've met some interesting folk in Raffles Class and was wondering if the F class clientele is stereotypically male and middle-aged, or whether the converse holds true...
DoctorWu