Was this in lieu of pay?

Reader-added tags for now consist of "Obvious booby trap" and "You won't hook me in with bait like that-kasaaa!" (Parody of the memetic line by 2ch JIS character Kuma.)

Sanae:

Since you've drawn the flier art, now you have to go, don't you.

That is rather strange social norm, what kind of idea or culture led to this kind of norm?

RikoShigeru said:

That is rather strange social norm, what kind of idea or culture led to this kind of norm?

I mean, if people see that a familiar artist has drawn the flier art, it's not a huge leap of logic to assume that the artist is participating otherwise as well. Hard to say how much of a "social norm" it is, though, or how serious Kogasa is being.