I wonder if they even know what NO SOLICITING means... I'm kind of surprised that there are still door-to-door salespeople these days. Here in Japan about the only two types of people who ring the doorbell are mormons and the NHK police trying to get money.
It is possible with the education these days they may not know what it means. Yeah, we get companies trying to sell Internet, Pest control, and other services all the time. They are supposed to have permits from the town as well to do door-to-door, but most don't.