In previous eras, tattoos were perceived to be the calling card of an outlaw or a sailor. Within the public eye, their presence on the skin of another person meant that trouble was close by.
They may have flashed past you, on the arm of a leather-clad biker, or the neck of a drunken sailor, looking for trouble. If they came into your business, you may have been more likely to call the police than to offer them a job.