Maybe less common in America, but in Europe it's not uncommon to have multiple people going around town delivering various things to your mailbox: a postman for letters, some poor student delivering grocery store brochures once a week, somebody delivering the local newspaper at the break of dawn, somebody else delivering the local church newspaper once a month, etc. And all of them are going door to door. If just one of them is an openstreetmap fan you quickly have all doorbell cameras in their delivery district mapped