….show you a card and tell you they’re selling stuff in order to prove to ‘whoever’ that, having misbehaved in the past, they are now on the straight and narrow and eager to work. I had one such person on my doorstep today. He told me he’d been in trouble - nothing terrible - and asked if I would buy his wares in order to help him secure employment in the future. I felt sorry for him, but since he seemed particularly interested in my unseen barking dog, I sent him away.
The best and simplest thing to do is to say to cold callers on the doorstep:
"If you are genuine, you won't mind my taking your photograph, will you ?"
I bet they all leg it, pronto.