I usually just point them to the video of Harlan Ellison cursing out someone who asked him to write for free.
@oldtex59 @starbreaker Yow! Overkill much?
Nope. I forget how many people have wanted to shoot photos "for exposure" after years working for major magazines....
People die from exposure.
Know any shop keepers who take exposure as payment? Me neither.
Harlan is only one of many science fiction writers who can wield a biting tongue.