Grandfather clauses do exist and do cover most activities going on prior to the enactment of an ordinance that might limit that activity within the designated area in the future. You could say that I have Goats, chickens and Bees due to a grandfather clause. My area, until this last year was zoned residential/agricultural so the keeping of such livestock (bees are livestock) is allowed as long as I continue to maintain their presence on my property. This is a standard legal practice based on the injustice of making something illegal after the fact. The activity is not illegal until an ordinance is passed against it and then only from that point on. A grandfather clause allows the continuation of customary activities.