i'm not 100% correct - but i believe if you wear anything other than an approved suit, then you are considered wearing a wetsuit.
also - i remember looking into calf high neoprine socks and good timing watch that was audible and - i can't remember where - i thought i read a rule that said no accessories are allowed except a cap and goggles and a noseplug?
Thanks - do you use these for training or just cold water protection?
I use them to keep my feet warm when I am doing open water workouts in the winter. They do help quite a bit.