Having spent many years in flower shops, I assure you loads of people do not know their mothers address, it never gets flagged up as being wrong, because the postie, has 'the knowledge', they just know (in rural areas at any rate) that Mrs Violet Sweetsmell lives @ number 39 and not 89, as it said on the envelope and slot the letter in the right place in their delivery run. All fine and dandy till you need a bouquet of flowers delivering or an ambulance, that's called by a third party; by which time a wreath might be more appropriate. If you query the address with the customer, they just tell you 'Ask in the village, everyone knows her.' Time consuming for florists and I don't imagine ambulances can go looking for patients by broadcasting the patients name around the village. (It's best not get me going on a rant about houses with no numbers or names on them)