i never heard of it happening before,but from what you say,it seems that if there is money being braught into the home from a business or an income generating hobby, it woulod be classed by them as a business premises so they cant offer a home owners policy on the same property as it would probly cause confusion in the event of a claim, if the cause of fire or what ever accident was caused by an item used by the business of by the home itself.maybe im wrong but from what i see this is why.