But in the UK it will be passported as bay and everyone will understand it as bay regardless of the genes. Common usage of words are not always technically correct by other people's definitions. If they ever start testing for colours and documenting them following that then things might change...but I somehow doubt it over here.
I hear you though. Australia is very much like the UK in colour terms. If I had a dollar for every time I heard skewbald, or someone called a buckskin a dun, or a grey a roan...