Yeah I'd have a moment of self-loathing too if I'd made someone wait at the door under such a thunderstorm... BTW the text on the sweater is the "I want a billion yen" (70.3 million Norwegian kroner, 5.9 million euros) in the tweet from two chapters ago.
I mean, if it was a circular notice of course it would have been bad, but this one seems to have been a charity beggar of some sort?
But I guess it's mean to leave those out in the rain as well, even if they might be annoying and have a hard time taking no for an answer.
Edit: Chapter 19 implies that it either was a salesperson or a deliveryperson.
Edit 2: Chapter 17 of the extras volume seem to have her as a mailman, so yes it's impressive they manage to be so happy despite the weather and it's a bad thing to hide and make them have to stay out longer.