What do you do with that very troublesome 3 wishes per day and planar binding or even worse the true name discovery?
True Name - Oh look, someone killed the genie.
Planar Binding - The genie won't agree unless payed an enormous sum of money, at least the equivilent to each casting of wish.
Simply don't let it be abused. One funny thought would be to have the enemy of the PCs get an Efreeti that wishes the inhierent bonuses to be lowered each day :).
If your players are chain-binding genies then I would be fair and warn them that corruption of wishes is possible.
IIRC there is a monster(maybe an inevitable) that tracks such people down.
I just read the true name discovery. I see no reason why it can't tell other monsters about its problems once it is released.
The True Name discovery says the monster "must obey you to the best of its ability, without pay or bargaining for its services". It never says the monster can't retaliate later.
The players should be warned of such things up front, and I would also tell them to stop trying to game the system, and that the next time they won't get any warnings.
Now I have to look for that monster that hates it when people abuse wishes.
If it's something the players are continually exploiting, have the efreet plot to kill these pesky mortals. Maybe he calls in some allies to help him out. Maybe he's the vassal of a Malik who doesn't appreciate his underling being pulled away all the time.
And of course, you could always twist the wishes into harmful consequences. Popular culture is rife with examples (see Wishmaster. Or don't: it wasn't a particularly good movie.)
It seems no such creature exist, but sending a boss level strike voice after the player if he exist lets him know that there are in game consequences to action, and talking to him outside of the game lets him know you don't like it, and that everything the rules allows should not be done.
What does a lawful evil creature from a very war-like race that has Plane Shift do? Hmm, I don't know.
I want to make an alteration to my previous comment. If the character is going to fool around with outsider without using knowledge checks to find out why it is a bad idea you are justified in whatever bad things you have the effreti do to him. If the party chooses to risk their lives and help him, then that is their fault. If they are smart they will not interfere.
Keep in mind that virtually every wish can be corrupted, though it will be less likely if they pay proper tribute. Also create flaws in wishes that might not be readily apparent at first > limited duration, side effects, wished items belonged to a powerful entity, wishing for riches turns the PCs sword to pure gold making it near useless or worse his familiar, wife henchman or himself
it is also fair game to say they just can't do it
roleplay the entire thing it is easier to make mistakes when they are in the middle of the action
Have the efreeti attempt vengeance, supplying the PCs nemesis with wishes specifically tailored to bring ruin to the PCs.
To those saying that they can't bind them, let's be serious a wizard focusing enough and with a little time in his hands he can bind them just fine.
To those saying corrupt the wishes, although i detest the idea (i really do because something the player can put out clearly doesn't mean that the character can and vice versa) i might do that but i am thinking that the only thing they are going to be asking is for everyone to get +3 to every ability and duplicating high level spells (and maybe a resuraction now and then).
What do you think about the idea that the efreeti (as a race) can only grant 3 wishes per person? doesn't matter what efreeti you called, you only get 3 wishes in your lifetime.
One of the APs has information about this, including an article about wishes, and an NPC group that might come after someone who is abusing them.