Perhaps we need a definition of a sink. Recall when we had to install GFCIs in bathrooms, all of a sudden no one knew what a bathroom was, next code cycle (75?) we had a bathroom definition.
Same issue in 2002 when commercial kitchens required GFCI, all of a sudden " what is a kitchen". Turns out an employee break room with a microwave and sink is not a kitchen.
In Washington our code rules fixed that, a kitchen is somewhere that dishes are washed or food/beverages are prepared. So now, if you wash dishes in a metal garden tub, is that a kitchen???