Quote Originally Posted by Tzardok View Post
I like to draw on lore from older editions where 3.x remains silent, and because of that I have to emphatically support this. According to Secrets of the Lamp (a 2e sourcebook and the only sourcebook on genies in all editions), efreets get audited by the Grand Sultan's officials after granting wishes and get punished if it is determined that they didn't put enough effort into screwing over the mortal. They are governmentally mandated to be malicious genies.
Imagining Robin Williams' genie going on the lam after being freed from his lamp. That's the real reason he went off to see the world. He was avoiding a subpoena.

Quote Originally Posted by AMFV View Post
This again requires DM adjudication though. And we're back to where we started.
Strictly speaking, the entire game runs on DM mandate. There's no way to parse a wish without it having to go through a human element - and in this case, the DM has very little reason to read the wish charitably - after all, it's being given to an evil outsider.

I would say the "pay market value" bit is a good way to avoid the worst possible outcomes, but there's still the very real chance that the efreet says it doesn't want to play and takes its ball and goes home. Done diplomatically, at least, it's less likely to end in one out for your head/other thematically appropriate body parts.