i think that is a good rule of thumb for people you don’t know that well but there are exceptions. for instance while i might talk to someone on plurk often but never one on one, i would ask and discuss it with them. for my friend that i’ve know for a long time and who i will dm “hey i found this mpreg yaoi doujin where a hot elf man gets raped by orcs and thought it was your thing” and she replies “hell yeah thanks for the link” is someone who i will spring surprise commissions on.

it’s still not a bad rule to go by but it’s not something that’s set in stone.